165634380901 has 6 divisors (see below), whose sum is σ = 182060931206. Its totient is φ = 150576709800.

The previous prime is 165634380881. The next prime is 165634380911. The reversal of 165634380901 is 109083436561.

It can be written as a sum of positive squares in only one way, i.e., 164835188001 + 799192900 = 405999^2 + 28270^2 .

It is not a de Polignac number, because 165634380901 - 2⁹ = 165634380389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165634380911) 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, 684439470 + ... + 684439711.

Almost surely, 2^165634380901 is an apocalyptic number.

165634380901 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165634380901 is a deficient number, since it is larger than the sum of its proper divisors (16426550305).

165634380901 is a wasteful number, since it uses less digits than its factorization.

165634380901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368879203 (or 1368879192 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 46.

It can be divided in two parts, 165634 and 380901, that added together give a triangular number (546535 = T₁₀₄₅).

The spelling of 165634380901 in words is "one hundred sixty-five billion, six hundred thirty-four million, three hundred eighty thousand, nine hundred one".