660747557 has 2 divisors, whose sum is σ = 660747558. Its totient is φ = 660747556.

The previous prime is 660747541. The next prime is 660747569. The reversal of 660747557 is 755747066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 398760961 + 261986596 = 19969^2 + 16186^2 .

It is a cyclic number.

It is not a de Polignac number, because 660747557 - 2⁴ = 660747541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660737557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330373778 + 330373779.

It is an arithmetic number, because the mean of its divisors is an integer number (330373779).

Almost surely, 2^660747557 is an apocalyptic number.

It is an amenable number.

660747557 is a deficient number, since it is larger than the sum of its proper divisors (1).

660747557 is an equidigital number, since it uses as much as digits as its factorization.

660747557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1234800, while the sum is 47.

The square root of 660747557 is about 25705.0103481792. The cubic root of 660747557 is about 870.9873658217.

The spelling of 660747557 in words is "six hundred sixty million, seven hundred forty-seven thousand, five hundred fifty-seven".