21204172453 has 8 divisors (see below), whose sum is σ = 21889865216. Its totient is φ = 20518585200.

The previous prime is 21204172447. The next prime is 21204172477. The reversal of 21204172453 is 35427140212.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21204172453 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204172853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 699808 + ... + 729478.

It is an arithmetic number, because the mean of its divisors is an integer number (2736233152).

Almost surely, 2^21204172453 is an apocalyptic number.

It is an amenable number.

21204172453 is a deficient number, since it is larger than the sum of its proper divisors (685692763).

21204172453 is a wasteful number, since it uses less digits than its factorization.

21204172453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52755.

The product of its (nonzero) digits is 13440, while the sum is 31.

The spelling of 21204172453 in words is "twenty-one billion, two hundred four million, one hundred seventy-two thousand, four hundred fifty-three".