21660157333791 has 6 divisors (see below), whose sum is σ = 31286893926600. Its totient is φ = 14440104889188.

The previous prime is 21660157333769. The next prime is 21660157333799. The reversal of 21660157333791 is 19733375106612.

It is a happy number.

21660157333791 is a `hidden beast` number, since 2 + 1 + 6 + 60 + 1 + 573 + 3 + 3 + 7 + 9 + 1 = 666.

It is not a de Polignac number, because 21660157333791 - 2⁷ = 21660157333663 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660157333799) 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, 1203342074091 + ... + 1203342074108.

It is an arithmetic number, because the mean of its divisors is an integer number (5214482321100).

Almost surely, 2^{21660157333791} is an apocalyptic number.

21660157333791 is a deficient number, since it is larger than the sum of its proper divisors (9626736592809).

21660157333791 is a wasteful number, since it uses less digits than its factorization.

21660157333791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2406684148205 (or 2406684148202 counting only the distinct ones).

The product of its (nonzero) digits is 4286520, while the sum is 54.

The spelling of 21660157333791 in words is "twenty-one trillion, six hundred sixty billion, one hundred fifty-seven million, three hundred thirty-three thousand, seven hundred ninety-one".