21632867920 has 20 divisors (see below), whose sum is σ = 50296418100. Its totient is φ = 8653147136.

The previous prime is 21632867899. The next prime is 21632867923. The reversal of 21632867920 is 2976823612.

It can be written as a sum of positive squares in 2 ways, for example, as 10844306496 + 10788561424 = 104136^2 + 103868^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21632867923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135205345 + ... + 135205504.

It is an arithmetic number, because the mean of its divisors is an integer number (2514820905).

Almost surely, 2^21632867920 is an apocalyptic number.

21632867920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21632867920 is an abundant number, since it is smaller than the sum of its proper divisors (28663550180).

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

21632867920 is a wasteful number, since it uses less digits than its factorization.

21632867920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270410862 (or 270410856 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 46.

The spelling of 21632867920 in words is "twenty-one billion, six hundred thirty-two million, eight hundred sixty-seven thousand, nine hundred twenty".