165815805355813 has 4 divisors (see below), whose sum is σ = 165899593031040. Its totient is φ = 165732017680588.

The previous prime is 165815805355747. The next prime is 165815805355841. The reversal of 165815805355813 is 318553508518561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165815805355813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165815805353813) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41893834645 + ... + 41893838602.

It is an arithmetic number, because the mean of its divisors is an integer number (41474898257760).

Almost surely, 2^{165815805355813} is an apocalyptic number.

It is an amenable number.

165815805355813 is a deficient number, since it is larger than the sum of its proper divisors (83787675227).

165815805355813 is an equidigital number, since it uses as much as digits as its factorization.

165815805355813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83787675226.

The product of its (nonzero) digits is 86400000, while the sum is 64.

The spelling of 165815805355813 in words is "one hundred sixty-five trillion, eight hundred fifteen billion, eight hundred five million, three hundred fifty-five thousand, eight hundred thirteen".