21656283180 has 96 divisors (see below), whose sum is σ = 71535636480. Its totient is φ = 4790327040.

The previous prime is 21656283137. The next prime is 21656283191. The reversal of 21656283180 is 8138265612.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 818635 + ... + 844674.

It is an arithmetic number, because the mean of its divisors is an integer number (745162880).

Almost surely, 2^21656283180 is an apocalyptic number.

21656283180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21656283180 is an abundant number, since it is smaller than the sum of its proper divisors (49879353300).

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

21656283180 is a wasteful number, since it uses less digits than its factorization.

21656283180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1663359 (or 1663357 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 21656283180 in words is "twenty-one billion, six hundred fifty-six million, two hundred eighty-three thousand, one hundred eighty".