77661666 has 40 divisors (see below), whose sum is σ = 174566700. Its totient is φ = 25805952.

The previous prime is 77661653. The next prime is 77661673. The reversal of 77661666 is 66616677.

It can be written as a sum of positive squares in 2 ways, for example, as 63441225 + 14220441 = 7965^2 + 3771^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 73510 + ... + 74558.

Almost surely, 2^77661666 is an apocalyptic number.

77661666 is an abundant number, since it is smaller than the sum of its proper divisors (96905034).

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

77661666 is a wasteful number, since it uses less digits than its factorization.

77661666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520 (or 1511 counting only the distinct ones).

The product of its digits is 381024, while the sum is 45.

The square root of 77661666 is about 8812.5856591582. The cubic root of 77661666 is about 426.6472011248.

The spelling of 77661666 in words is "seventy-seven million, six hundred sixty-one thousand, six hundred sixty-six".