21437265 has 16 divisors (see below), whose sum is σ = 35791488. Its totient is φ = 10935936.

The previous prime is 21437261. The next prime is 21437279. The reversal of 21437265 is 56273412.

It is not a de Polignac number, because 21437265 - 2² = 21437261 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21437261) 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, 30724 + ... + 31413.

It is an arithmetic number, because the mean of its divisors is an integer number (2236968).

Almost surely, 2^21437265 is an apocalyptic number.

It is an amenable number.

21437265 is a deficient number, since it is larger than the sum of its proper divisors (14354223).

21437265 is a wasteful number, since it uses less digits than its factorization.

21437265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62168.

The product of its digits is 10080, while the sum is 30.

The square root of 21437265 is about 4630.0394166789. The cubic root of 21437265 is about 277.7941690179.

The spelling of 21437265 in words is "twenty-one million, four hundred thirty-seven thousand, two hundred sixty-five".