21791867166975 has 24 divisors (see below), whose sum is σ = 36029436488320. Its totient is φ = 11622259444320.

The previous prime is 21791867166869. The next prime is 21791867167003. The reversal of 21791867166975 is 57966176819712.

It is a Cunningham number, because it is equal to 4668176²-1.

It is not a de Polignac number, because 21791867166975 - 2¹¹ = 21791867164927 is a prime.

It is a Smith number, since the sum of its digits (75) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (75).

It is a junction number, because it is equal to n+sod(n) for n = 21791867166897 and 21791867166906.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13226496 + ... + 14782554.

Almost surely, 2^{21791867166975} is an apocalyptic number.

21791867166975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21791867166975 is a deficient number, since it is larger than the sum of its proper divisors (14237569321345).

21791867166975 is a wasteful number, since it uses less digits than its factorization.

21791867166975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1742799 (or 1742794 counting only the distinct ones).

The product of its digits is 480090240, while the sum is 75.

The spelling of 21791867166975 in words is "twenty-one trillion, seven hundred ninety-one billion, eight hundred sixty-seven million, one hundred sixty-six thousand, nine hundred seventy-five".