21723354225 has 24 divisors (see below), whose sum is σ = 39906607520. Its totient is φ = 11585788560.

The previous prime is 21723354179. The next prime is 21723354251. The reversal of 21723354225 is 52245332712.

21723354225 is a `hidden beast` number, since 21 + 72 + 3 + 3 + 542 + 25 = 666.

It is not a de Polignac number, because 21723354225 - 2¹⁷ = 21723223153 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21723354225.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16090699 + ... + 16092048.

Almost surely, 2^21723354225 is an apocalyptic number.

21723354225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21723354225 is a deficient number, since it is larger than the sum of its proper divisors (18183253295).

21723354225 is a wasteful number, since it uses less digits than its factorization.

21723354225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32182766 (or 32182755 counting only the distinct ones).

The product of its digits is 100800, while the sum is 36.

Adding to 21723354225 its reverse (52245332712), we get a palindrome (73968686937).

The spelling of 21723354225 in words is "twenty-one billion, seven hundred twenty-three million, three hundred fifty-four thousand, two hundred twenty-five".