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870 = 23529

• 870 can be written using four 4's:

See also 113.
870 has 16 divisors (see below), whose sum is σ = 2160. Its totient is φ = 224.

The previous prime is 863. The next prime is 877. The reversal of 870 is 78.

870 is nontrivially palindromic in base 12.

It is an interprime number because it is at equal distance from previous prime (863) and next prime (877).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an alternating number because its digits alternate between even and odd.

870 is an undulating number in base 12.

It is a Curzon number.

It is a plaindrome in base 9 and base 16.

It is a nialpdrome in base 10 and base 11.

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16 + ... + 44.

It is an arithmetic number, because the mean of its divisors is an integer number (135).

It is the magic constant of a 12 × 12 magic square.

It is a pronic number, being equal to 29×30.

It is a practical number, because each smaller number is the sum of distinct divisors of 870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1080).

870 is an abundant number, since it is smaller than the sum of its proper divisors (1290).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

870 is a wasteful number, since it uses less digits than its factorization.

870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 870 is about 29.4957624075. The cubic root of 870 is about 9.5464027094.

It can be divided in two parts, 8 and 70, that added together give a triangular number (78 = T12).

The spelling of 870 in words is "eight hundred seventy", and thus it is an aban number and an oban number.

Divisors: 1 2 3 5 6 10 15 29 30 58 87 145 174 290 435 870