21264395 has 16 divisors (see below), whose sum is σ = 26904960. Its totient is φ = 16109184.

The previous prime is 21264391. The next prime is 21264413. The reversal of 21264395 is 59346212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21264395 - 2² = 21264391 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21264391) 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, 6302 + ... + 9068.

It is an arithmetic number, because the mean of its divisors is an integer number (1681560).

Almost surely, 2^21264395 is an apocalyptic number.

21264395 is a deficient number, since it is larger than the sum of its proper divisors (5640565).

21264395 is a wasteful number, since it uses less digits than its factorization.

21264395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2854.

The product of its digits is 12960, while the sum is 32.

The square root of 21264395 is about 4611.3333212857. Note that the first 4 decimals coincide. The cubic root of 21264395 is about 277.0454425483.

The spelling of 21264395 in words is "twenty-one million, two hundred sixty-four thousand, three hundred ninety-five".