21057184980 has 384 divisors, whose sum is σ = 75483394560. Its totient is φ = 4827340800.

The previous prime is 21057184969. The next prime is 21057185069. The reversal of 21057184980 is 8948175012.

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

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 12052467 + ... + 12054213.

It is an arithmetic number, because the mean of its divisors is an integer number (196571340).

Almost surely, 2^21057184980 is an apocalyptic number.

21057184980 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 21057184980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37741697280).

21057184980 is an abundant number, since it is smaller than the sum of its proper divisors (54426209580).

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

21057184980 is a wasteful number, since it uses less digits than its factorization.

21057184980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1896 (or 1888 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 21057184980 in words is "twenty-one billion, fifty-seven million, one hundred eighty-four thousand, nine hundred eighty".