21092910920 has 16 divisors (see below), whose sum is σ = 47459049660. Its totient is φ = 8437164352.

The previous prime is 21092910899. The next prime is 21092910941. The reversal of 21092910920 is 2901929012.

It is an interprime number because it is at equal distance from previous prime (21092910899) and next prime (21092910941).

It can be written as a sum of positive squares in 2 ways, for example, as 19252672516 + 1840238404 = 138754^2 + 42898^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263661347 + ... + 263661426.

Almost surely, 2^21092910920 is an apocalyptic number.

21092910920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21092910920 is an abundant number, since it is smaller than the sum of its proper divisors (26366138740).

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

21092910920 is a wasteful number, since it uses less digits than its factorization.

21092910920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527322784 (or 527322780 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 35.

The spelling of 21092910920 in words is "twenty-one billion, ninety-two million, nine hundred ten thousand, nine hundred twenty".