64665990 has 24 divisors (see below), whose sum is σ = 168131808. Its totient is φ = 17244240.

The previous prime is 64665971. The next prime is 64666009. The reversal of 64665990 is 9956646.

It is an interprime number because it is at equal distance from previous prime (64665971) and next prime (64666009).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 359166 + ... + 359345.

It is an arithmetic number, because the mean of its divisors is an integer number (7005492).

Almost surely, 2^64665990 is an apocalyptic number.

64665990 is an abundant number, since it is smaller than the sum of its proper divisors (103465818).

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

64665990 is a wasteful number, since it uses less digits than its factorization.

64665990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718524 (or 718521 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The square root of 64665990 is about 8041.5166479962. The cubic root of 64665990 is about 401.3826940523.

The spelling of 64665990 in words is "sixty-four million, six hundred sixty-five thousand, nine hundred ninety".