64166512565 has 4 divisors (see below), whose sum is σ = 76999815084. Its totient is φ = 51333210048.

The previous prime is 64166512547. The next prime is 64166512591. The reversal of 64166512565 is 56521566146.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15962553649 + 48203958916 = 126343^2 + 219554^2 .

It is a cyclic number.

It is not a de Polignac number, because 64166512565 - 2¹⁴ = 64166496181 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, 6416651252 + ... + 6416651261.

It is an arithmetic number, because the mean of its divisors is an integer number (19249953771).

Almost surely, 2^64166512565 is an apocalyptic number.

It is an amenable number.

64166512565 is a deficient number, since it is larger than the sum of its proper divisors (12833302519).

64166512565 is a wasteful number, since it uses less digits than its factorization.

64166512565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12833302518.

The product of its digits is 1296000, while the sum is 47.

The spelling of 64166512565 in words is "sixty-four billion, one hundred sixty-six million, five hundred twelve thousand, five hundred sixty-five".