21294553 has 4 divisors (see below), whose sum is σ = 24336640. Its totient is φ = 18252468.

The previous prime is 21294541. The next prime is 21294571. The reversal of 21294553 is 35549212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21294553 - 2¹⁷ = 21163481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21294253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1521033 + ... + 1521046.

It is an arithmetic number, because the mean of its divisors is an integer number (6084160).

Almost surely, 2^21294553 is an apocalyptic number.

It is an amenable number.

21294553 is a deficient number, since it is larger than the sum of its proper divisors (3042087).

21294553 is an equidigital number, since it uses as much as digits as its factorization.

21294553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3042086.

The product of its digits is 10800, while the sum is 31.

The square root of 21294553 is about 4614.6021496983. The cubic root of 21294553 is about 277.1763529223.

The spelling of 21294553 in words is "twenty-one million, two hundred ninety-four thousand, five hundred fifty-three".