64991976 has 64 divisors (see below), whose sum is σ = 189665280. Its totient is φ = 18171840.

The previous prime is 64991933. The next prime is 64991977. The reversal of 64991976 is 67919946.

It is not an unprimeable number, because it can be changed into a prime (64991977) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 3781 + ... + 12011.

It is an arithmetic number, because the mean of its divisors is an integer number (2963520).

Almost surely, 2^64991976 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 64991976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94832640).

64991976 is an abundant number, since it is smaller than the sum of its proper divisors (124673304).

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

64991976 is a wasteful number, since it uses less digits than its factorization.

64991976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8294 (or 8290 counting only the distinct ones).

The product of its digits is 734832, while the sum is 51.

The square root of 64991976 is about 8061.7601055849. The cubic root of 64991976 is about 402.0560304070.

The spelling of 64991976 in words is "sixty-four million, nine hundred ninety-one thousand, nine hundred seventy-six".