21377925 has 96 divisors (see below), whose sum is σ = 43925760. Its totient is φ = 10264320.

The previous prime is 21377861. The next prime is 21377929. The reversal of 21377925 is 52977312.

It is not a de Polignac number, because 21377925 - 2⁶ = 21377861 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21377925.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21377929) by changing a digit.

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, 929464 + ... + 929486.

It is an arithmetic number, because the mean of its divisors is an integer number (457560).

Almost surely, 2^21377925 is an apocalyptic number.

21377925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21377925 is an abundant number, since it is smaller than the sum of its proper divisors (22547835).

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

21377925 is an equidigital number, since it uses as much as digits as its factorization.

21377925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71 (or 48 counting only the distinct ones).

The product of its digits is 26460, while the sum is 36.

The square root of 21377925 is about 4623.6268231768. The cubic root of 21377925 is about 277.5376136012.

The spelling of 21377925 in words is "twenty-one million, three hundred seventy-seven thousand, nine hundred twenty-five".