21264331 has 12 divisors (see below), whose sum is σ = 24645960. Its totient is φ = 18191360.

The previous prime is 21264323. The next prime is 21264349. The reversal of 21264331 is 13346212.

It is not a de Polignac number, because 21264331 - 2³ = 21264323 is a prime.

It is a super-2 number, since 2×21264331² = 904343545755122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21264361) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166 + ... + 6523.

It is an arithmetic number, because the mean of its divisors is an integer number (2053830).

Almost surely, 2^21264331 is an apocalyptic number.

21264331 is a deficient number, since it is larger than the sum of its proper divisors (3381629).

21264331 is a wasteful number, since it uses less digits than its factorization.

21264331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6734 (or 6717 counting only the distinct ones).

The product of its digits is 864, while the sum is 22.

The square root of 21264331 is about 4611.3263818559. The cubic root of 21264331 is about 277.0451646044.

The spelling of 21264331 in words is "twenty-one million, two hundred sixty-four thousand, three hundred thirty-one".