64661550 has 24 divisors (see below), whose sum is σ = 160361016. Its totient is φ = 17243040.

The previous prime is 64661543. The next prime is 64661563. The reversal of 64661550 is 5516646.

It is a super-3 number, since 3×64661550³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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, 215389 + ... + 215688.

It is an arithmetic number, because the mean of its divisors is an integer number (6681709).

Almost surely, 2^64661550 is an apocalyptic number.

64661550 is an abundant number, since it is smaller than the sum of its proper divisors (95699466).

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

64661550 is a wasteful number, since it uses less digits than its factorization.

64661550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431092 (or 431087 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 64661550 is about 8041.2405759311. The cubic root of 64661550 is about 401.3735074616.

The spelling of 64661550 in words is "sixty-four million, six hundred sixty-one thousand, five hundred fifty".