21519231408 has 30 divisors (see below), whose sum is σ = 60223960524. Its totient is φ = 7173077088.

The previous prime is 21519231401. The next prime is 21519231443. The reversal of 21519231408 is 80413291512.

21519231408 is a `hidden beast` number, since 2 + 1 + 5 + 19 + 231 + 408 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21519231401) 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, 74719410 + ... + 74719697.

Almost surely, 2^21519231408 is an apocalyptic number.

It is an amenable number.

21519231408 is an abundant number, since it is smaller than the sum of its proper divisors (38704729116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21519231408 is a wasteful number, since it uses less digits than its factorization.

21519231408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149439121 (or 149439112 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 21519231408 in words is "twenty-one billion, five hundred nineteen million, two hundred thirty-one thousand, four hundred eight".