64215978 has 16 divisors (see below), whose sum is σ = 128532096. Its totient is φ = 21388640.

The previous prime is 64215967. The next prime is 64215997. The reversal of 64215978 is 87951246.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 7 ways as a sum of consecutive naturals, for example, 6118 + ... + 12878.

It is an arithmetic number, because the mean of its divisors is an integer number (8033256).

Almost surely, 2^64215978 is an apocalyptic number.

64215978 is an abundant number, since it is smaller than the sum of its proper divisors (64316118).

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

64215978 is a wasteful number, since it uses less digits than its factorization.

64215978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8349.

The product of its digits is 120960, while the sum is 42.

The square root of 64215978 is about 8013.4872558706. The cubic root of 64215978 is about 400.4494489666.

The spelling of 64215978 in words is "sixty-four million, two hundred fifteen thousand, nine hundred seventy-eight".