165557401 has 2 divisors, whose sum is σ = 165557402. Its totient is φ = 165557400.

The previous prime is 165557387. The next prime is 165557411. The reversal of 165557401 is 104755561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135745801 + 29811600 = 11651^2 + 5460^2 .

It is an emirp because it is prime and its reverse (104755561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165557401 - 2²⁷ = 31339673 is a prime.

It is not a weakly prime, because it can be changed into another prime (165557411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82778700 + 82778701.

It is an arithmetic number, because the mean of its divisors is an integer number (82778701).

Almost surely, 2^165557401 is an apocalyptic number.

It is an amenable number.

165557401 is a deficient number, since it is larger than the sum of its proper divisors (1).

165557401 is an equidigital number, since it uses as much as digits as its factorization.

165557401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21000, while the sum is 34.

The square root of 165557401 is about 12866.9110900791. The cubic root of 165557401 is about 549.0975846299.

The spelling of 165557401 in words is "one hundred sixty-five million, five hundred fifty-seven thousand, four hundred one".