64999978 has 8 divisors (see below), whose sum is σ = 101739168. Its totient is φ = 31086924.

The previous prime is 64999943. The next prime is 64999981. The reversal of 64999978 is 87999946.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 706476 + ... + 706567.

It is an arithmetic number, because the mean of its divisors is an integer number (12717396).

Almost surely, 2^64999978 is an apocalyptic number.

64999978 is a deficient number, since it is larger than the sum of its proper divisors (36739190).

64999978 is a wasteful number, since it uses less digits than its factorization.

64999978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1413068.

The product of its digits is 8817984, while the sum is 61.

The square root of 64999978 is about 8062.2563839164. The cubic root of 64999978 is about 402.0725304969.

The spelling of 64999978 in words is "sixty-four million, nine hundred ninety-nine thousand, nine hundred seventy-eight".