21264047 has 24 divisors (see below), whose sum is σ = 26215200. Its totient is φ = 16873920.

The previous prime is 21264037. The next prime is 21264053. The reversal of 21264047 is 74046212.

It is not a de Polignac number, because 21264047 - 2⁴ = 21264031 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21264017) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 195029 + ... + 195137.

It is an arithmetic number, because the mean of its divisors is an integer number (1092300).

Almost surely, 2^21264047 is an apocalyptic number.

21264047 is a deficient number, since it is larger than the sum of its proper divisors (4951153).

21264047 is a wasteful number, since it uses less digits than its factorization.

21264047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 21264047 is about 4611.2955880099. The cubic root of 21264047 is about 277.0439312217.

The spelling of 21264047 in words is "twenty-one million, two hundred sixty-four thousand, forty-seven".