165657550091 has 16 divisors (see below), whose sum is σ = 185161788000. Its totient is φ = 146895513600.

The previous prime is 165657550057. The next prime is 165657550103. The reversal of 165657550091 is 190055756561.

It is not a de Polignac number, because 165657550091 - 2¹⁸ = 165657287947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165657558091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2423795 + ... + 2491203.

It is an arithmetic number, because the mean of its divisors is an integer number (11572611750).

Almost surely, 2^165657550091 is an apocalyptic number.

165657550091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165657550091 is a deficient number, since it is larger than the sum of its proper divisors (19504237909).

165657550091 is a wasteful number, since it uses less digits than its factorization.

165657550091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72910.

The product of its (nonzero) digits is 1417500, while the sum is 50.

The spelling of 165657550091 in words is "one hundred sixty-five billion, six hundred fifty-seven million, five hundred fifty thousand, ninety-one".