66808641 has 8 divisors (see below), whose sum is σ = 90206080. Its totient is φ = 43975152.

The previous prime is 66808633. The next prime is 66808661. The reversal of 66808641 is 14680866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66808641 - 2³ = 66808633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66808641.

It is not an unprimeable number, because it can be changed into a prime (66808601) 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, 140710 + ... + 141183.

It is an arithmetic number, because the mean of its divisors is an integer number (11275760).

Almost surely, 2^66808641 is an apocalyptic number.

It is an amenable number.

66808641 is a deficient number, since it is larger than the sum of its proper divisors (23397439).

66808641 is a wasteful number, since it uses less digits than its factorization.

66808641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281975.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 66808641 is about 8173.6553022500. The cubic root of 66808641 is about 405.7677678088.

The spelling of 66808641 in words is "sixty-six million, eight hundred eight thousand, six hundred forty-one".