64515631 has 4 divisors (see below), whose sum is σ = 65888352. Its totient is φ = 63142912.

The previous prime is 64515623. The next prime is 64515637. The reversal of 64515631 is 13651546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13651546 = 2 ⋅6825773.

It is a cyclic number.

It is not a de Polignac number, because 64515631 - 2³ = 64515623 is a prime.

It is a super-2 number, since 2×64515631² = 8324533286656322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64515593 and 64515602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64515637) 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, 686290 + ... + 686383.

It is an arithmetic number, because the mean of its divisors is an integer number (16472088).

Almost surely, 2^64515631 is an apocalyptic number.

64515631 is a deficient number, since it is larger than the sum of its proper divisors (1372721).

64515631 is a wasteful number, since it uses less digits than its factorization.

64515631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1372720.

The product of its digits is 10800, while the sum is 31.

The square root of 64515631 is about 8032.1622867071. The cubic root of 64515631 is about 401.0713591620.

The spelling of 64515631 in words is "sixty-four million, five hundred fifteen thousand, six hundred thirty-one".