8661433978 has 16 divisors (see below), whose sum is σ = 13759375680. Its totient is φ = 4080596256.

The previous prime is 8661433939. The next prime is 8661433997. The reversal of 8661433978 is 8793341668.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1402083 + ... + 1408246.

It is an arithmetic number, because the mean of its divisors is an integer number (859960980).

Almost surely, 2^8661433978 is an apocalyptic number.

8661433978 is a deficient number, since it is larger than the sum of its proper divisors (5097941702).

8661433978 is a wasteful number, since it uses less digits than its factorization.

8661433978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2810421.

The product of its digits is 5225472, while the sum is 55.

The square root of 8661433978 is about 93066.8253353471. The cubic root of 8661433978 is about 2053.6665675072. Note that the first 3 decimals are identical.

The spelling of 8661433978 in words is "eight billion, six hundred sixty-one million, four hundred thirty-three thousand, nine hundred seventy-eight".