64991860 has 12 divisors (see below), whose sum is σ = 136482948. Its totient is φ = 25996736.

The previous prime is 64991831. The next prime is 64991873. The reversal of 64991860 is 6819946.

It can be written as a sum of positive squares in 2 ways, for example, as 19131876 + 45859984 = 4374^2 + 6772^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1624777 + ... + 1624816.

It is an arithmetic number, because the mean of its divisors is an integer number (11373579).

Almost surely, 2^64991860 is an apocalyptic number.

It is an amenable number.

64991860 is an abundant number, since it is smaller than the sum of its proper divisors (71491088).

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

64991860 is a wasteful number, since it uses less digits than its factorization.

64991860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3249602 (or 3249600 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 64991860 is about 8061.7529111230. The cubic root of 64991860 is about 402.0557912056.

The spelling of 64991860 in words is "sixty-four million, nine hundred ninety-one thousand, eight hundred sixty".