21556030680 has 192 divisors, whose sum is σ = 71514200160. Its totient is φ = 5629138944.

The previous prime is 21556030669. The next prime is 21556030729. The reversal of 21556030680 is 8603065512.

21556030680 is a `hidden beast` number, since 2 + 1 + 5 + 560 + 30 + 68 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18068164 + ... + 18069356.

Almost surely, 2^21556030680 is an apocalyptic number.

21556030680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21556030680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35757100080).

21556030680 is an abundant number, since it is smaller than the sum of its proper divisors (49958169480).

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

21556030680 is a wasteful number, since it uses less digits than its factorization.

21556030680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2210 (or 2203 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 21556030680 in words is "twenty-one billion, five hundred fifty-six million, thirty thousand, six hundred eighty".