21156501700 has 72 divisors (see below), whose sum is σ = 50723753472. Its totient is φ = 7618490880.

The previous prime is 21156501697. The next prime is 21156501719. The reversal of 21156501700 is 710565112.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 231444 + ... + 309643.

It is an arithmetic number, because the mean of its divisors is an integer number (704496576).

Almost surely, 2^21156501700 is an apocalyptic number.

21156501700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21156501700 is an abundant number, since it is smaller than the sum of its proper divisors (29567251772).

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

21156501700 is a wasteful number, since it uses less digits than its factorization.

21156501700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541141 (or 541134 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 28.

The spelling of 21156501700 in words is "twenty-one billion, one hundred fifty-six million, five hundred one thousand, seven hundred".