165209431 has 2 divisors, whose sum is σ = 165209432. Its totient is φ = 165209430.

The previous prime is 165209357. The next prime is 165209441. The reversal of 165209431 is 134902561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165209431 - 2⁹ = 165208919 is a prime.

It is a super-2 number, since 2×165209431² = 54588312182687522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 165209393 and 165209402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165209441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82604715 + 82604716.

It is an arithmetic number, because the mean of its divisors is an integer number (82604716).

Almost surely, 2^165209431 is an apocalyptic number.

165209431 is a deficient number, since it is larger than the sum of its proper divisors (1).

165209431 is an equidigital number, since it uses as much as digits as its factorization.

165209431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 165209431 is about 12853.3820841053. The cubic root of 165209431 is about 548.7126154173.

The spelling of 165209431 in words is "one hundred sixty-five million, two hundred nine thousand, four hundred thirty-one".