165421519 has 2 divisors, whose sum is σ = 165421520. Its totient is φ = 165421518.

The previous prime is 165421517. The next prime is 165421547. The reversal of 165421519 is 915124561.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165421519 - 2¹ = 165421517 is a prime.

It is a super-2 number, since 2×165421519² = 54728557896534722, which contains 22 as substring.

Together with 165421517, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165421513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82710759 + 82710760.

It is an arithmetic number, because the mean of its divisors is an integer number (82710760).

Almost surely, 2^165421519 is an apocalyptic number.

165421519 is a deficient number, since it is larger than the sum of its proper divisors (1).

165421519 is an equidigital number, since it uses as much as digits as its factorization.

165421519 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 34.

The square root of 165421519 is about 12861.6297178857. The cubic root of 165421519 is about 548.9473187207.

The spelling of 165421519 in words is "one hundred sixty-five million, four hundred twenty-one thousand, five hundred nineteen".