66409986 has 16 divisors (see below), whose sum is σ = 133555968. Its totient is φ = 22014000.

The previous prime is 66409979. The next prime is 66409991. The reversal of 66409986 is 68990466.

66409986 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29490 + ... + 31661.

It is an arithmetic number, because the mean of its divisors is an integer number (8347248).

Almost surely, 2^66409986 is an apocalyptic number.

66409986 is an abundant number, since it is smaller than the sum of its proper divisors (67145982).

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

66409986 is a wasteful number, since it uses less digits than its factorization.

66409986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61337.

The product of its (nonzero) digits is 559872, while the sum is 48.

The square root of 66409986 is about 8149.2322337752. The cubic root of 66409986 is about 404.9590691755.

The spelling of 66409986 in words is "sixty-six million, four hundred nine thousand, nine hundred eighty-six".