165983961 has 32 divisors (see below), whose sum is σ = 267055488. Its totient is φ = 90339840.

The previous prime is 165983959. The next prime is 165983963. The reversal of 165983961 is 169389561.

It is an interprime number because it is at equal distance from previous prime (165983959) and next prime (165983963).

It is not a de Polignac number, because 165983961 - 2¹ = 165983959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165983961.

It is not an unprimeable number, because it can be changed into a prime (165983963) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10645 + ... + 21101.

It is an arithmetic number, because the mean of its divisors is an integer number (8345484).

Almost surely, 2^165983961 is an apocalyptic number.

165983961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165983961 is a deficient number, since it is larger than the sum of its proper divisors (101071527).

165983961 is a wasteful number, since it uses less digits than its factorization.

165983961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10521.

The product of its digits is 349920, while the sum is 48.

The square root of 165983961 is about 12883.4762777753. The cubic root of 165983961 is about 549.5687650030.

The spelling of 165983961 in words is "one hundred sixty-five million, nine hundred eighty-three thousand, nine hundred sixty-one".