21151718700 has 72 divisors (see below), whose sum is σ = 69941690112. Its totient is φ = 4834678080.

The previous prime is 21151718647. The next prime is 21151718723. The reversal of 21151718700 is 781715112.

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, 5034024 + ... + 5038223.

Almost surely, 2^21151718700 is an apocalyptic number.

21151718700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21151718700 is an abundant number, since it is smaller than the sum of its proper divisors (48789971412).

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

21151718700 is a wasteful number, since it uses less digits than its factorization.

21151718700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10072271 (or 10072264 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 33.

The spelling of 21151718700 in words is "twenty-one billion, one hundred fifty-one million, seven hundred eighteen thousand, seven hundred".