165401491 has 2 divisors, whose sum is σ = 165401492. Its totient is φ = 165401490.

The previous prime is 165401447. The next prime is 165401497. The reversal of 165401491 is 194104561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165401491 - 2⁷ = 165401363 is a prime.

It is not a weakly prime, because it can be changed into another prime (165401497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82700745 + 82700746.

It is an arithmetic number, because the mean of its divisors is an integer number (82700746).

Almost surely, 2^165401491 is an apocalyptic number.

165401491 is a deficient number, since it is larger than the sum of its proper divisors (1).

165401491 is an equidigital number, since it uses as much as digits as its factorization.

165401491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 165401491 is about 12860.8510993635. The cubic root of 165401491 is about 548.9251636816.

The spelling of 165401491 in words is "one hundred sixty-five million, four hundred one thousand, four hundred ninety-one".