660734621 has 2 divisors, whose sum is σ = 660734622. Its totient is φ = 660734620.

The previous prime is 660734611. The next prime is 660734629. The reversal of 660734621 is 126437066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 426216025 + 234518596 = 20645^2 + 15314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660734621 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 (660734629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330367310 + 330367311.

It is an arithmetic number, because the mean of its divisors is an integer number (330367311).

Almost surely, 2^660734621 is an apocalyptic number.

It is an amenable number.

660734621 is a deficient number, since it is larger than the sum of its proper divisors (1).

660734621 is an equidigital number, since it uses as much as digits as its factorization.

660734621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 660734621 is about 25704.7587228513. The cubic root of 660734621 is about 870.9816817718.

The spelling of 660734621 in words is "six hundred sixty million, seven hundred thirty-four thousand, six hundred twenty-one".