66672691 has 16 divisors (see below), whose sum is σ = 74856960. Its totient is φ = 59011200.

The previous prime is 66672679. The next prime is 66672707. The reversal of 66672691 is 19627666.

It is a cyclic number.

It is not a de Polignac number, because 66672691 - 2²⁵ = 33118259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66670691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48090 + ... + 49456.

It is an arithmetic number, because the mean of its divisors is an integer number (4678560).

Almost surely, 2^66672691 is an apocalyptic number.

66672691 is a deficient number, since it is larger than the sum of its proper divisors (8184269).

66672691 is a wasteful number, since it uses less digits than its factorization.

66672691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1554.

The product of its digits is 163296, while the sum is 43.

The square root of 66672691 is about 8165.3347145111. The cubic root of 66672691 is about 405.4923464078.

The spelling of 66672691 in words is "sixty-six million, six hundred seventy-two thousand, six hundred ninety-one".