64991525 has 6 divisors (see below), whose sum is σ = 80589522. Its totient is φ = 51993200.

The previous prime is 64991513. The next prime is 64991543. The reversal of 64991525 is 52519946.

It can be written as a sum of positive squares in 3 ways, for example, as 124609 + 64866916 = 353^2 + 8054^2 .

It is a de Polignac number, because none of the positive numbers 2^k-64991525 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 5 ways as a sum of consecutive naturals, for example, 1299806 + ... + 1299855.

It is an arithmetic number, because the mean of its divisors is an integer number (13431587).

Almost surely, 2^64991525 is an apocalyptic number.

It is an amenable number.

64991525 is a deficient number, since it is larger than the sum of its proper divisors (15597997).

64991525 is a wasteful number, since it uses less digits than its factorization.

64991525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2599671 (or 2599666 counting only the distinct ones).

The product of its digits is 97200, while the sum is 41.

The square root of 64991525 is about 8061.7321339772. The cubic root of 64991525 is about 402.0551004067.

The spelling of 64991525 in words is "sixty-four million, nine hundred ninety-one thousand, five hundred twenty-five".