861709056 has 144 divisors (see below), whose sum is σ = 2615616864. Its totient is φ = 249495552.

The previous prime is 861709049. The next prime is 861709061. The reversal of 861709056 is 650907168.

It is a super-2 number, since 2×861709056² = 1485084994384822272, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 861708999 and 861709017.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167190 + ... + 172266.

It is an arithmetic number, because the mean of its divisors is an integer number (18164006).

Almost surely, 2^861709056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861709056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1307808432).

861709056 is an abundant number, since it is smaller than the sum of its proper divisors (1753907808).

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

861709056 is a wasteful number, since it uses less digits than its factorization.

861709056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5126 (or 5112 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 861709056 is about 29354.8812976650. The cubic root of 861709056 is about 951.5980696263.

The spelling of 861709056 in words is "eight hundred sixty-one million, seven hundred nine thousand, fifty-six".