21115670720 has 56 divisors (see below), whose sum is σ = 52467869664. Its totient is φ = 8079036416.

The previous prime is 21115670707. The next prime is 21115670761. The reversal of 21115670720 is 2707651112.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1427129 + ... + 1441848.

It is an arithmetic number, because the mean of its divisors is an integer number (936926244).

Almost surely, 2^21115670720 is an apocalyptic number.

21115670720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115670720 is an abundant number, since it is smaller than the sum of its proper divisors (31352198944).

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

21115670720 is a wasteful number, since it uses less digits than its factorization.

21115670720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2869017 (or 2869007 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 32.

The spelling of 21115670720 in words is "twenty-one billion, one hundred fifteen million, six hundred seventy thousand, seven hundred twenty".