21255453 has 16 divisors (see below), whose sum is σ = 31881600. Its totient is φ = 14168844.

The previous prime is 21255449. The next prime is 21255467. The reversal of 21255453 is 35455212.

It is a happy number.

It is not a de Polignac number, because 21255453 - 2² = 21255449 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255653) 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 15 ways as a sum of consecutive naturals, for example, 2673 + ... + 7046.

It is an arithmetic number, because the mean of its divisors is an integer number (1992600).

Almost surely, 2^21255453 is an apocalyptic number.

It is an amenable number.

21255453 is a deficient number, since it is larger than the sum of its proper divisors (10626147).

21255453 is an frugal number, since it uses more digits than its factorization.

21255453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9740 (or 9722 counting only the distinct ones).

The product of its digits is 6000, while the sum is 27.

The square root of 21255453 is about 4610.3636516006. The cubic root of 21255453 is about 277.0066031695.

The spelling of 21255453 in words is "twenty-one million, two hundred fifty-five thousand, four hundred fifty-three".