21690951900 has 72 divisors (see below), whose sum is σ = 63380620464. Its totient is φ = 5726976000.

The previous prime is 21690951881. The next prime is 21690951943. The reversal of 21690951900 is 915909612.

It is a happy number.

It is a super-2 number, since 2×21690951900² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 327637 + ... + 388236.

Almost surely, 2^21690951900 is an apocalyptic number.

21690951900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21690951900 is an abundant number, since it is smaller than the sum of its proper divisors (41689668564).

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

21690951900 is a wasteful number, since it uses less digits than its factorization.

21690951900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715991 (or 715984 counting only the distinct ones).

The product of its (nonzero) digits is 43740, while the sum is 42.

The spelling of 21690951900 in words is "twenty-one billion, six hundred ninety million, nine hundred fifty-one thousand, nine hundred".