660667291 has 4 divisors (see below), whose sum is σ = 667478392. Its totient is φ = 653856192.

The previous prime is 660667279. The next prime is 660667303. The reversal of 660667291 is 192766066.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (660667279) and next prime (660667303).

It is a cyclic number.

It is not a de Polignac number, because 660667291 - 2⁹ = 660666779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660667211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3405405 + ... + 3405598.

It is an arithmetic number, because the mean of its divisors is an integer number (166869598).

Almost surely, 2^660667291 is an apocalyptic number.

660667291 is a deficient number, since it is larger than the sum of its proper divisors (6811101).

660667291 is an equidigital number, since it uses as much as digits as its factorization.

660667291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6811100.

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

The square root of 660667291 is about 25703.4490098119. The cubic root of 660667291 is about 870.9520959206.

The spelling of 660667291 in words is "six hundred sixty million, six hundred sixty-seven thousand, two hundred ninety-one".