21437955 has 96 divisors (see below), whose sum is σ = 48522240. Its totient is φ = 8490240.

The previous prime is 21437939. The next prime is 21437963. The reversal of 21437955 is 55973412.

It is not a de Polignac number, because 21437955 - 2⁴ = 21437939 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 79561 + ... + 79829.

It is an arithmetic number, because the mean of its divisors is an integer number (505440).

Almost surely, 2^21437955 is an apocalyptic number.

21437955 is an abundant number, since it is smaller than the sum of its proper divisors (27084285).

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

21437955 is a wasteful number, since it uses less digits than its factorization.

21437955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321 (or 318 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 21437955 is about 4630.1139294838. The cubic root of 21437955 is about 277.7971494342.

The spelling of 21437955 in words is "twenty-one million, four hundred thirty-seven thousand, nine hundred fifty-five".