642765965 has 4 divisors (see below), whose sum is σ = 771319164. Its totient is φ = 514212768.

The previous prime is 642765943. The next prime is 642765973. The reversal of 642765965 is 569567246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 569567246 = 2 ⋅284783623.

It can be written as a sum of positive squares in 2 ways, for example, as 152497801 + 490268164 = 12349^2 + 22142^2 .

It is a cyclic number.

It is not a de Polignac number, because 642765965 - 2⁶ = 642765901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64276592 + ... + 64276601.

It is an arithmetic number, because the mean of its divisors is an integer number (192829791).

Almost surely, 2^642765965 is an apocalyptic number.

It is an amenable number.

642765965 is a deficient number, since it is larger than the sum of its proper divisors (128553199).

642765965 is a wasteful number, since it uses less digits than its factorization.

642765965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128553198.

The product of its digits is 2721600, while the sum is 50.

The square root of 642765965 is about 25352.8295265045. The cubic root of 642765965 is about 863.0135690947.

The spelling of 642765965 in words is "six hundred forty-two million, seven hundred sixty-five thousand, nine hundred sixty-five".