870721638 has 8 divisors (see below), whose sum is σ = 1741443288. Its totient is φ = 290240544.

The previous prime is 870721637. The next prime is 870721667. The reversal of 870721638 is 836127078.

870721638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

870721638 is an admirable number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 870721638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (870721637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72560131 + ... + 72560142.

It is an arithmetic number, because the mean of its divisors is an integer number (217680411).

Almost surely, 2^870721638 is an apocalyptic number.

870721638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

870721638 is a wasteful number, since it uses less digits than its factorization.

870721638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145120278.

The product of its (nonzero) digits is 112896, while the sum is 42.

The square root of 870721638 is about 29507.9927816177. The cubic root of 870721638 is about 954.9041461500.

The spelling of 870721638 in words is "eight hundred seventy million, seven hundred twenty-one thousand, six hundred thirty-eight".