21255520100 has 36 divisors (see below), whose sum is σ = 46487691264. Its totient is φ = 8435256480.

The previous prime is 21255520067. The next prime is 21255520151. The reversal of 21255520100 is 102555212.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 824132 + ... + 849531.

Almost surely, 2^21255520100 is an apocalyptic number.

21255520100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21255520100 is an abundant number, since it is smaller than the sum of its proper divisors (25232171164).

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

21255520100 is a wasteful number, since it uses less digits than its factorization.

21255520100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1673804 (or 1673797 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 23.

The spelling of 21255520100 in words is "twenty-one billion, two hundred fifty-five million, five hundred twenty thousand, one hundred".