556861201920 has 640 divisors, whose sum is σ = 2018622228480. Its totient is φ = 145477140480.

The previous prime is 556861201907. The next prime is 556861201957. The reversal of 556861201920 is 29102168655.

556861201920 is a `hidden beast` number, since 5 + 5 + 6 + 8 + 612 + 0 + 1 + 9 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1143451917 + ... + 1143452403.

It is an arithmetic number, because the mean of its divisors is an integer number (3154097232).

Almost surely, 2^556861201920 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 556861201920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1009311114240).

556861201920 is an abundant number, since it is smaller than the sum of its proper divisors (1461761026560).

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

556861201920 is a wasteful number, since it uses less digits than its factorization.

556861201920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823 (or 801 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 556861201920 in words is "five hundred fifty-six billion, eight hundred sixty-one million, two hundred one thousand, nine hundred twenty".