21291453 has 12 divisors (see below), whose sum is σ = 30959968. Its totient is φ = 14099400.

The previous prime is 21291449. The next prime is 21291467. The reversal of 21291453 is 35419212.

It is not a de Polignac number, because 21291453 - 2² = 21291449 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21296453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6475 + ... + 9192.

Almost surely, 2^21291453 is an apocalyptic number.

It is an amenable number.

21291453 is a deficient number, since it is larger than the sum of its proper divisors (9668515).

21291453 is a wasteful number, since it uses less digits than its factorization.

21291453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15824 (or 15821 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21291453 is about 4614.2662471947. The cubic root of 21291453 is about 277.1629020898.

The spelling of 21291453 in words is "twenty-one million, two hundred ninety-one thousand, four hundred fifty-three".