21625375 has 16 divisors (see below), whose sum is σ = 27245088. Its totient is φ = 17136000.

The previous prime is 21625367. The next prime is 21625391. The reversal of 21625375 is 57352612.

It is not a de Polignac number, because 21625375 - 2³ = 21625367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13360 + ... + 14890.

It is an arithmetic number, because the mean of its divisors is an integer number (1702818).

Almost surely, 2^21625375 is an apocalyptic number.

21625375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21625375 is a deficient number, since it is larger than the sum of its proper divisors (5619713).

21625375 is a wasteful number, since it uses less digits than its factorization.

21625375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659 (or 1649 counting only the distinct ones).

The product of its digits is 12600, while the sum is 31.

The square root of 21625375 is about 4650.3091295096. The cubic root of 21625375 is about 278.6043431882.

Adding to 21625375 its reverse (57352612), we get a palindrome (78977987).

The spelling of 21625375 in words is "twenty-one million, six hundred twenty-five thousand, three hundred seventy-five".