21453181623 has 6 divisors (see below), whose sum is σ = 30987929024. Its totient is φ = 14302121076.

The previous prime is 21453181613. The next prime is 21453181669. The reversal of 21453181623 is 32618135412.

21453181623 is a `hidden beast` number, since 2 + 1 + 453 + 181 + 6 + 23 = 666.

It is not a de Polignac number, because 21453181623 - 2⁶ = 21453181559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21453181613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1191843415 + ... + 1191843432.

Almost surely, 2^21453181623 is an apocalyptic number.

21453181623 is a deficient number, since it is larger than the sum of its proper divisors (9534747401).

21453181623 is a wasteful number, since it uses less digits than its factorization.

21453181623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2383686853 (or 2383686850 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The spelling of 21453181623 in words is "twenty-one billion, four hundred fifty-three million, one hundred eighty-one thousand, six hundred twenty-three".