21396375 has 192 divisors, whose sum is σ = 54512640. Its totient is φ = 7776000.

The previous prime is 21396317. The next prime is 21396379. The reversal of 21396375 is 57369312.

21396375 is a `hidden beast` number, since 2 + 13 + 9 + 637 + 5 = 666.

It is not a de Polignac number, because 21396375 - 2⁸ = 21396119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21396379) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1126116 + ... + 1126134.

It is an arithmetic number, because the mean of its divisors is an integer number (283920).

Almost surely, 2^21396375 is an apocalyptic number.

21396375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21396375 is an abundant number, since it is smaller than the sum of its proper divisors (33116265).

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

21396375 is a wasteful number, since it uses less digits than its factorization.

21396375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71 (or 58 counting only the distinct ones).

The product of its digits is 34020, while the sum is 36.

The square root of 21396375 is about 4625.6215798528. The cubic root of 21396375 is about 277.6174326450.

The spelling of 21396375 in words is "twenty-one million, three hundred ninety-six thousand, three hundred seventy-five".