21125965 has 16 divisors (see below), whose sum is σ = 29174400. Its totient is φ = 14385600.

The previous prime is 21125939. The next prime is 21125969. The reversal of 21125965 is 56952112.

It is not a de Polignac number, because 21125965 - 2⁵ = 21125933 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3190 + ... + 7240.

It is an arithmetic number, because the mean of its divisors is an integer number (1823400).

Almost surely, 2^21125965 is an apocalyptic number.

It is an amenable number.

21125965 is a deficient number, since it is larger than the sum of its proper divisors (8048435).

21125965 is a wasteful number, since it uses less digits than its factorization.

21125965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4212.

The product of its digits is 5400, while the sum is 31.

The square root of 21125965 is about 4596.2990546743. The cubic root of 21125965 is about 276.4429499040.

The spelling of 21125965 in words is "twenty-one million, one hundred twenty-five thousand, nine hundred sixty-five".