861556312836 has 96 divisors (see below), whose sum is σ = 2369760986880. Its totient is φ = 269754527232.

The previous prime is 861556312807. The next prime is 861556312867. The reversal of 861556312836 is 638213655168.

It is a happy number.

861556312836 is a `hidden beast` number, since 8 + 6 + 1 + 556 + 3 + 1 + 2 + 83 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 457050 + ... + 1389966.

It is an arithmetic number, because the mean of its divisors is an integer number (24685010280).

Almost surely, 2^861556312836 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 861556312836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1184880493440).

861556312836 is an abundant number, since it is smaller than the sum of its proper divisors (1508204674044).

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

861556312836 is a wasteful number, since it uses less digits than its factorization.

861556312836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933450 (or 933442 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 54.

The spelling of 861556312836 in words is "eight hundred sixty-one billion, five hundred fifty-six million, three hundred twelve thousand, eight hundred thirty-six".