66864641 has 8 divisors (see below), whose sum is σ = 69284160. Its totient is φ = 64488112.

The previous prime is 66864617. The next prime is 66864647. The reversal of 66864641 is 14646866.

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

It is a cyclic number.

It is not a de Polignac number, because 66864641 - 2¹⁰ = 66863617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66864647) 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, 7565 + ... + 13818.

It is an arithmetic number, because the mean of its divisors is an integer number (8660520).

Almost surely, 2^66864641 is an apocalyptic number.

It is an amenable number.

66864641 is a deficient number, since it is larger than the sum of its proper divisors (2419519).

66864641 is a wasteful number, since it uses less digits than its factorization.

66864641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21495.

The product of its digits is 165888, while the sum is 41.

The square root of 66864641 is about 8177.0802246279. The cubic root of 66864641 is about 405.8811096794.

The spelling of 66864641 in words is "sixty-six million, eight hundred sixty-four thousand, six hundred forty-one".