165508649 has 2 divisors, whose sum is σ = 165508650. Its totient is φ = 165508648.

The previous prime is 165508633. The next prime is 165508663. The reversal of 165508649 is 946805561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158256400 + 7252249 = 12580^2 + 2693^2 .

It is a cyclic number.

It is not a de Polignac number, because 165508649 - 2⁴ = 165508633 is a prime.

It is a super-2 number, since 2×165508649² = 54786225787610402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (165508669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82754324 + 82754325.

It is an arithmetic number, because the mean of its divisors is an integer number (82754325).

Almost surely, 2^165508649 is an apocalyptic number.

It is an amenable number.

165508649 is a deficient number, since it is larger than the sum of its proper divisors (1).

165508649 is an equidigital number, since it uses as much as digits as its factorization.

165508649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 165508649 is about 12865.0164788079. The cubic root of 165508649 is about 549.0436814049.

The spelling of 165508649 in words is "one hundred sixty-five million, five hundred eight thousand, six hundred forty-nine".