660331291 has 4 divisors (see below), whose sum is σ = 661994992. Its totient is φ = 658667592.

The previous prime is 660331277. The next prime is 660331303. The reversal of 660331291 is 192133066.

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

It is a cyclic number.

It is not a de Polignac number, because 660331291 - 2¹⁵ = 660298523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660331201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 831255 + ... + 832048.

It is an arithmetic number, because the mean of its divisors is an integer number (165498748).

Almost surely, 2^660331291 is an apocalyptic number.

660331291 is a deficient number, since it is larger than the sum of its proper divisors (1663701).

660331291 is a wasteful number, since it uses less digits than its factorization.

660331291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1663700.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 660331291 is about 25696.9120907552. The cubic root of 660331291 is about 870.8044222316.

The spelling of 660331291 in words is "six hundred sixty million, three hundred thirty-one thousand, two hundred ninety-one".