64939660 has 48 divisors (see below), whose sum is σ = 145061280. Its totient is φ = 24335360.

The previous prime is 64939621. The next prime is 64939661. The reversal of 64939660 is 6693946.

It is not an unprimeable number, because it can be changed into a prime (64939661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132015 + ... + 132505.

It is an arithmetic number, because the mean of its divisors is an integer number (3022110).

Almost surely, 2^64939660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64939660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72530640).

64939660 is an abundant number, since it is smaller than the sum of its proper divisors (80121620).

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

64939660 is a wasteful number, since it uses less digits than its factorization.

64939660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906 (or 904 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 43.

The square root of 64939660 is about 8058.5147514911. The cubic root of 64939660 is about 401.9481216520.

The spelling of 64939660 in words is "sixty-four million, nine hundred thirty-nine thousand, six hundred sixty".