21572193951 has 48 divisors (see below), whose sum is σ = 40893315840. Its totient is φ = 10616520960.

The previous prime is 21572193919. The next prime is 21572193977. The reversal of 21572193951 is 15939127512.

21572193951 is a `hidden beast` number, since 21 + 572 + 1 + 9 + 3 + 9 + 51 = 666.

It is not a de Polignac number, because 21572193951 - 2⁵ = 21572193919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21572193897 and 21572193906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21572193901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 806010 + ... + 832343.

It is an arithmetic number, because the mean of its divisors is an integer number (851944080).

Almost surely, 2^21572193951 is an apocalyptic number.

21572193951 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21572193951 is a deficient number, since it is larger than the sum of its proper divisors (19321121889).

21572193951 is a wasteful number, since it uses less digits than its factorization.

21572193951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638396 (or 1638393 counting only the distinct ones).

The product of its digits is 170100, while the sum is 45.

The spelling of 21572193951 in words is "twenty-one billion, five hundred seventy-two million, one hundred ninety-three thousand, nine hundred fifty-one".