21654589880 has 256 divisors, whose sum is σ = 61887006720. Its totient is φ = 6624000000.

The previous prime is 21654589877. The next prime is 21654589927. The reversal of 21654589880 is 8898545612.

It is a Harshad number since it is a multiple of its sum of digits (56).

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 63 ways as a sum of consecutive naturals, for example, 46972850 + ... + 46973310.

It is an arithmetic number, because the mean of its divisors is an integer number (241746120).

Almost surely, 2^21654589880 is an apocalyptic number.

21654589880 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 21654589880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30943503360).

21654589880 is an abundant number, since it is smaller than the sum of its proper divisors (40232416840).

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

21654589880 is a wasteful number, since it uses less digits than its factorization.

21654589880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 742 (or 738 counting only the distinct ones).

The product of its (nonzero) digits is 5529600, while the sum is 56.

The spelling of 21654589880 in words is "twenty-one billion, six hundred fifty-four million, five hundred eighty-nine thousand, eight hundred eighty".