811856909556 has 288 divisors, whose sum is σ = 2646412634880. Its totient is φ = 210684672000.

The previous prime is 811856909543. The next prime is 811856909579. The reversal of 811856909556 is 655909658118.

811856909556 is a `hidden beast` number, since 8 + 1 + 18 + 5 + 69 + 0 + 9 + 556 = 666.

811856909556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×811856909556² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 811856909493 and 811856909502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 124495576 + ... + 124502096.

It is an arithmetic number, because the mean of its divisors is an integer number (9188932760).

Almost surely, 2^811856909556 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 811856909556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1323206317440).

811856909556 is an abundant number, since it is smaller than the sum of its proper divisors (1834555725324).

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

811856909556 is a wasteful number, since it uses less digits than its factorization.

811856909556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7924 (or 7905 counting only the distinct ones).

The product of its (nonzero) digits is 23328000, while the sum is 63.

The spelling of 811856909556 in words is "eight hundred eleven billion, eight hundred fifty-six million, nine hundred nine thousand, five hundred fifty-six".