78666669 has 12 divisors (see below), whose sum is σ = 119610400. Its totient is φ = 49684104.

The previous prime is 78666661. The next prime is 78666671. The reversal of 78666669 is 96666687.

It is not a de Polignac number, because 78666669 - 2³ = 78666661 is a prime.

It is a super-2 number, since 2×78666669² = 12376889623111122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78666661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 229849 + ... + 230190.

Almost surely, 2^78666669 is an apocalyptic number.

It is an amenable number.

78666669 is a deficient number, since it is larger than the sum of its proper divisors (40943731).

78666669 is a wasteful number, since it uses less digits than its factorization.

78666669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460064 (or 460061 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 54.

The square root of 78666669 is about 8869.4232619714. The cubic root of 78666669 is about 428.4797024171.

It can be divided in two parts, 7866 and 6669, that added together give a triangular number (14535 = T₁₇₀).

The spelling of 78666669 in words is "seventy-eight million, six hundred sixty-six thousand, six hundred sixty-nine".