21264533 has 4 divisors (see below), whose sum is σ = 21277740. Its totient is φ = 21251328.

The previous prime is 21264521. The next prime is 21264541. The reversal of 21264533 is 33546212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10387729 + 10876804 = 3223^2 + 3298^2 .

It is a cyclic number.

It is not a de Polignac number, because 21264533 - 2¹⁶ = 21198997 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 (21264563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3788 + ... + 7541.

It is an arithmetic number, because the mean of its divisors is an integer number (5319435).

Almost surely, 2^21264533 is an apocalyptic number.

It is an amenable number.

21264533 is a deficient number, since it is larger than the sum of its proper divisors (13207).

21264533 is a wasteful number, since it uses less digits than its factorization.

21264533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13206.

The product of its digits is 4320, while the sum is 26.

The square root of 21264533 is about 4611.3482843958. The cubic root of 21264533 is about 277.0460418629.

The spelling of 21264533 in words is "twenty-one million, two hundred sixty-four thousand, five hundred thirty-three".