21165875580 has 96 divisors (see below), whose sum is σ = 63836172288. Its totient is φ = 5224665600.

The previous prime is 21165875561. The next prime is 21165875593. The reversal of 21165875580 is 8557856112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 204601 + ... + 290160.

It is an arithmetic number, because the mean of its divisors is an integer number (664960128).

Almost surely, 2^21165875580 is an apocalyptic number.

21165875580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21165875580 is an abundant number, since it is smaller than the sum of its proper divisors (42670296708).

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

21165875580 is a wasteful number, since it uses less digits than its factorization.

21165875580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494827 (or 494825 counting only the distinct ones).

The product of its (nonzero) digits is 672000, while the sum is 48.

The spelling of 21165875580 in words is "twenty-one billion, one hundred sixty-five million, eight hundred seventy-five thousand, five hundred eighty".