165921314951 has 4 divisors (see below), whose sum is σ = 189624359952. Its totient is φ = 142218269952.

The previous prime is 165921314837. The next prime is 165921314971. The reversal of 165921314951 is 159413129561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165921314951 - 2²⁶ = 165854206087 is a prime.

It is a super-2 number, since 2×165921314951² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165921314896 and 165921314905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165921314971) 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, 11851522490 + ... + 11851522503.

It is an arithmetic number, because the mean of its divisors is an integer number (47406089988).

Almost surely, 2^165921314951 is an apocalyptic number.

165921314951 is a deficient number, since it is larger than the sum of its proper divisors (23703045001).

165921314951 is an equidigital number, since it uses as much as digits as its factorization.

165921314951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23703045000.

The product of its digits is 291600, while the sum is 47.

The spelling of 165921314951 in words is "one hundred sixty-five billion, nine hundred twenty-one million, three hundred fourteen thousand, nine hundred fifty-one".