660323861 has 2 divisors, whose sum is σ = 660323862. Its totient is φ = 660323860.

The previous prime is 660323837. The next prime is 660323869. The reversal of 660323861 is 168323066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641051761 + 19272100 = 25319^2 + 4390^2 .

It is a cyclic number.

It is not a de Polignac number, because 660323861 - 2²⁶ = 593214997 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660323869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330161930 + 330161931.

It is an arithmetic number, because the mean of its divisors is an integer number (330161931).

Almost surely, 2^660323861 is an apocalyptic number.

660323861 is the 13736-th centered heptagonal number.

It is an amenable number.

660323861 is a deficient number, since it is larger than the sum of its proper divisors (1).

660323861 is an equidigital number, since it uses as much as digits as its factorization.

660323861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 660323861 is about 25696.7675204489. The cubic root of 660323861 is about 870.8011561431.

The spelling of 660323861 in words is "six hundred sixty million, three hundred twenty-three thousand, eight hundred sixty-one".