165777776551 has 4 divisors (see below), whose sum is σ = 165792038832. Its totient is φ = 165763514272.

The previous prime is 165777776519. The next prime is 165777776561. The reversal of 165777776551 is 155677777561.

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 165777776551 - 2⁵ = 165777776519 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 (165777776501) 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, 7113691 + ... + 7136956.

It is an arithmetic number, because the mean of its divisors is an integer number (41448009708).

Almost surely, 2^165777776551 is an apocalyptic number.

165777776551 is a deficient number, since it is larger than the sum of its proper divisors (14262281).

165777776551 is a wasteful number, since it uses less digits than its factorization.

165777776551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14262280.

The product of its digits is 75631500, while the sum is 64.

The spelling of 165777776551 in words is "one hundred sixty-five billion, seven hundred seventy-seven million, seven hundred seventy-six thousand, five hundred fifty-one".