64686390 has 32 divisors (see below), whose sum is σ = 156854880. Its totient is φ = 17071104.

The previous prime is 64686389. The next prime is 64686403. The reversal of 64686390 is 9368646.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8205 + ... + 14024.

It is an arithmetic number, because the mean of its divisors is an integer number (4901715).

Almost surely, 2^64686390 is an apocalyptic number.

64686390 is an abundant number, since it is smaller than the sum of its proper divisors (92168490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64686390 is a wasteful number, since it uses less digits than its factorization.

64686390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22336.

The product of its (nonzero) digits is 186624, while the sum is 42.

The square root of 64686390 is about 8042.7849654209. The cubic root of 64686390 is about 401.4248973087.

It can be divided in two parts, 646863 and 90, that added together give a triangular number (646953 = T₁₁₃₇).

The spelling of 64686390 in words is "sixty-four million, six hundred eighty-six thousand, three hundred ninety".