166515720993 has 12 divisors (see below), whose sum is σ = 240526437840. Its totient is φ = 111008759256.

The previous prime is 166515720991. The next prime is 166515721019. The reversal of 166515720993 is 399027515661.

166515720993 is a `hidden beast` number, since 1 + 6 + 65 + 1 + 572 + 0 + 9 + 9 + 3 = 666.

It is not a de Polignac number, because 166515720993 - 2¹ = 166515720991 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166515720991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 786438 + ... + 975456.

It is an arithmetic number, because the mean of its divisors is an integer number (20043869820).

Almost surely, 2^166515720993 is an apocalyptic number.

It is an amenable number.

166515720993 is a deficient number, since it is larger than the sum of its proper divisors (74010716847).

166515720993 is a wasteful number, since it uses less digits than its factorization.

166515720993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286908 (or 286905 counting only the distinct ones).

The product of its (nonzero) digits is 3061800, while the sum is 54.

The spelling of 166515720993 in words is "one hundred sixty-six billion, five hundred fifteen million, seven hundred twenty thousand, nine hundred ninety-three".