91078779866 has 4 divisors (see below), whose sum is σ = 136618169802. Its totient is φ = 45539389932.

The previous prime is 91078779859. The next prime is 91078779877. The reversal of 91078779866 is 66897787019.

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., 57027828025 + 34050951841 = 238805^2 + 184529^2 .

It is a junction number, because it is equal to n+sod(n) for n = 91078779796 and 91078779805.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22769694965 + ... + 22769694968.

Almost surely, 2^91078779866 is an apocalyptic number.

91078779866 is a deficient number, since it is larger than the sum of its proper divisors (45539389936).

91078779866 is a wasteful number, since it uses less digits than its factorization.

91078779866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45539389935.

The product of its (nonzero) digits is 64012032, while the sum is 68.

The spelling of 91078779866 in words is "ninety-one billion, seventy-eight million, seven hundred seventy-nine thousand, eight hundred sixty-six".