21936729171 has 32 divisors (see below), whose sum is σ = 34551360000. Its totient is φ = 12120756480.

The previous prime is 21936729169. The next prime is 21936729179. The reversal of 21936729171 is 17192763912.

It is not a de Polignac number, because 21936729171 - 2¹ = 21936729169 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21936729171.

It is not an unprimeable number, because it can be changed into a prime (21936729179) 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 31 ways as a sum of consecutive naturals, for example, 69546 + ... + 220703.

It is an arithmetic number, because the mean of its divisors is an integer number (1079730000).

Almost surely, 2^21936729171 is an apocalyptic number.

21936729171 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21936729171 is a deficient number, since it is larger than the sum of its proper divisors (12614630829).

21936729171 is a wasteful number, since it uses less digits than its factorization.

21936729171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290379.

The product of its digits is 285768, while the sum is 48.

The spelling of 21936729171 in words is "twenty-one billion, nine hundred thirty-six million, seven hundred twenty-nine thousand, one hundred seventy-one".