21264553 has 8 divisors (see below), whose sum is σ = 22450400. Its totient is φ = 20085408.

The previous prime is 21264541. The next prime is 21264559. The reversal of 21264553 is 35546212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21264553 - 2⁵ = 21264521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21264559) 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 7 ways as a sum of consecutive naturals, for example, 5725 + ... + 8677.

It is an arithmetic number, because the mean of its divisors is an integer number (2806300).

Almost surely, 2^21264553 is an apocalyptic number.

It is an amenable number.

21264553 is a deficient number, since it is larger than the sum of its proper divisors (1185847).

21264553 is a wasteful number, since it uses less digits than its factorization.

21264553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3351.

The product of its digits is 7200, while the sum is 28.

The square root of 21264553 is about 4611.3504529584. The cubic root of 21264553 is about 277.0461287199.

The spelling of 21264553 in words is "twenty-one million, two hundred sixty-four thousand, five hundred fifty-three".