78387666 has 16 divisors (see below), whose sum is σ = 179171904. Its totient is φ = 22396464.

The previous prime is 78387643. The next prime is 78387707. The reversal of 78387666 is 66678387.

It is a super-2 number, since 2×78387666² = 12289252361855112, which contains 22 as substring.

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, 933145 + ... + 933228.

It is an arithmetic number, because the mean of its divisors is an integer number (11198244).

Almost surely, 2^78387666 is an apocalyptic number.

78387666 is an abundant number, since it is smaller than the sum of its proper divisors (100784238).

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

78387666 is a wasteful number, since it uses less digits than its factorization.

78387666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1866385.

The product of its digits is 2032128, while the sum is 51.

The square root of 78387666 is about 8853.6809294214. The cubic root of 78387666 is about 427.9725467877.

The spelling of 78387666 in words is "seventy-eight million, three hundred eighty-seven thousand, six hundred sixty-six".