21870160 has 80 divisors (see below), whose sum is σ = 58027536. Its totient is φ = 7593984.

The previous prime is 21870131. The next prime is 21870161. The reversal of 21870160 is 6107812.

It can be written as a sum of positive squares in 8 ways, for example, as 5184 + 21864976 = 72^2 + 4676^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17062 + ... + 18298.

Almost surely, 2^21870160 is an apocalyptic number.

21870160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21870160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29013768).

21870160 is an abundant number, since it is smaller than the sum of its proper divisors (36157376).

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

21870160 is a wasteful number, since it uses less digits than its factorization.

21870160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280 (or 1274 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21870160 is about 4676.5542870793. The cubic root of 21870160 is about 279.6516075057.

Adding to 21870160 its reverse (6107812), we get a palindrome (27977972).

The spelling of 21870160 in words is "twenty-one million, eight hundred seventy thousand, one hundred sixty".