64599981 has 8 divisors (see below), whose sum is σ = 90666720. Its totient is φ = 40799952.

The previous prime is 64599973. The next prime is 64600007. The reversal of 64599981 is 18999546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 64599981 - 2³ = 64599973 is a prime.

It is a super-2 number, since 2×64599981² = 8346315090400722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64599911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566610 + ... + 566723.

It is an arithmetic number, because the mean of its divisors is an integer number (11333340).

Almost surely, 2^64599981 is an apocalyptic number.

It is an amenable number.

64599981 is a deficient number, since it is larger than the sum of its proper divisors (26066739).

64599981 is a wasteful number, since it uses less digits than its factorization.

64599981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1133355.

The product of its digits is 699840, while the sum is 51.

The square root of 64599981 is about 8037.4113369915. The cubic root of 64599981 is about 401.2460746309.

The spelling of 64599981 in words is "sixty-four million, five hundred ninety-nine thousand, nine hundred eighty-one".