165900919 has 4 divisors (see below), whose sum is σ = 166284496. Its totient is φ = 165517344.

The previous prime is 165900901. The next prime is 165900961. The reversal of 165900919 is 919009561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919009561 = 3167 ⋅290183.

It is a cyclic number.

It is not a de Polignac number, because 165900919 - 2⁵ = 165900887 is a prime.

It is a super-2 number, since 2×165900919² = 55046229850089122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165903919) 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 in 3 ways as a sum of consecutive naturals, for example, 191139 + ... + 192004.

It is an arithmetic number, because the mean of its divisors is an integer number (41571124).

Almost surely, 2^165900919 is an apocalyptic number.

165900919 is a deficient number, since it is larger than the sum of its proper divisors (383577).

165900919 is an equidigital number, since it uses as much as digits as its factorization.

165900919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383576.

The product of its (nonzero) digits is 21870, while the sum is 40.

The square root of 165900919 is about 12880.2530642841. The cubic root of 165900919 is about 549.4770997159.

The spelling of 165900919 in words is "one hundred sixty-five million, nine hundred thousand, nine hundred nineteen".