21473534920 has 32 divisors (see below), whose sum is σ = 48325231800. Its totient is φ = 8587675648.

The previous prime is 21473534903. The next prime is 21473534923. The reversal of 21473534920 is 2943537412.

It can be written as a sum of positive squares in 4 ways, for example, as 18137086276 + 3336448644 = 134674^2 + 57762^2 .

It is a super-2 number, since 2×21473534920² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (21473534923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155832 + ... + 259288.

Almost surely, 2^21473534920 is an apocalyptic number.

21473534920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21473534920 is an abundant number, since it is smaller than the sum of its proper divisors (26851696880).

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

21473534920 is a wasteful number, since it uses less digits than its factorization.

21473534920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108657 (or 108653 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 40.

The spelling of 21473534920 in words is "twenty-one billion, four hundred seventy-three million, five hundred thirty-four thousand, nine hundred twenty".