21538317191472 has 100 divisors (see below), whose sum is σ = 62340366415800. Its totient is φ = 7179182502912.

The previous prime is 21538317191459. The next prime is 21538317191491. The reversal of 21538317191472 is 27419171383512.

21538317191472 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 83 + 1 + 7 + 1 + 91 + 472 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 37875904 + ... + 38440352.

It is an arithmetic number, because the mean of its divisors is an integer number (623403664158).

Almost surely, 2^{21538317191472} is an apocalyptic number.

It is an amenable number.

21538317191472 is an abundant number, since it is smaller than the sum of its proper divisors (40802049224328).

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

21538317191472 is a wasteful number, since it uses less digits than its factorization.

21538317191472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593912 (or 593897 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 54.

The spelling of 21538317191472 in words is "twenty-one trillion, five hundred thirty-eight billion, three hundred seventeen million, one hundred ninety-one thousand, four hundred seventy-two".