66686690 has 16 divisors (see below), whose sum is σ = 137184192. Its totient is φ = 22863984.

The previous prime is 66686681. The next prime is 66686693. The reversal of 66686690 is 9668666.

It is a super-2 number, since 2×66686690² = 8894229246312200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66686693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 476264 + ... + 476403.

It is an arithmetic number, because the mean of its divisors is an integer number (8574012).

Almost surely, 2^66686690 is an apocalyptic number.

66686690 is an abundant number, since it is smaller than the sum of its proper divisors (70497502).

66686690 is a wasteful number, since it uses less digits than its factorization.

66686690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 952681.

The product of its (nonzero) digits is 559872, while the sum is 47.

The square root of 66686690 is about 8166.1918909612. The cubic root of 66686690 is about 405.5207242940.

It can be divided in two parts, 66686 and 690, that added together give a palindrome (67376).

The spelling of 66686690 in words is "sixty-six million, six hundred eighty-six thousand, six hundred ninety".