7966553978 has 4 divisors (see below), whose sum is σ = 11949830970. Its totient is φ = 3983276988.

The previous prime is 7966553927. The next prime is 7966553989. The reversal of 7966553978 is 8793556697.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 5816655289 + 2149898689 = 76267^2 + 46367^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1991638493 + ... + 1991638496.

Almost surely, 2^7966553978 is an apocalyptic number.

7966553978 is a deficient number, since it is larger than the sum of its proper divisors (3983276992).

7966553978 is a wasteful number, since it uses less digits than its factorization.

7966553978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3983276991.

The product of its digits is 85730400, while the sum is 65.

The square root of 7966553978 is about 89255.5543257673. The cubic root of 7966553978 is about 1997.2089382992.

The spelling of 7966553978 in words is "seven billion, nine hundred sixty-six million, five hundred fifty-three thousand, nine hundred seventy-eight".