21264129 has 6 divisors (see below), whose sum is σ = 30714866. Its totient is φ = 14176080.

The previous prime is 21264119. The next prime is 21264149. The reversal of 21264129 is 92146212.

21264129 is a `hidden beast` number, since 2 + 12 + 641 + 2 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14837904 + 6426225 = 3852^2 + 2535^2 .

It is not a de Polignac number, because 21264129 - 2²¹ = 19166977 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21264119) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1181332 + ... + 1181349.

Almost surely, 2^21264129 is an apocalyptic number.

It is an amenable number.

21264129 is a deficient number, since it is larger than the sum of its proper divisors (9450737).

21264129 is a wasteful number, since it uses less digits than its factorization.

21264129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2362687 (or 2362684 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21264129 is about 4611.3044792119. The cubic root of 21264129 is about 277.0442873404.

The spelling of 21264129 in words is "twenty-one million, two hundred sixty-four thousand, one hundred twenty-nine".