661614467557 has 2 divisors, whose sum is σ = 661614467558. Its totient is φ = 661614467556.

The previous prime is 661614467537. The next prime is 661614467597. The reversal of 661614467557 is 755764416166.

It is a happy number.

661614467557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 493476745441 + 168137722116 = 702479^2 + 410046^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661614467557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661614467537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330807233778 + 330807233779.

It is an arithmetic number, because the mean of its divisors is an integer number (330807233779).

Almost surely, 2^661614467557 is an apocalyptic number.

It is an amenable number.

661614467557 is a deficient number, since it is larger than the sum of its proper divisors (1).

661614467557 is an equidigital number, since it uses as much as digits as its factorization.

661614467557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25401600, while the sum is 58.

The spelling of 661614467557 in words is "six hundred sixty-one billion, six hundred fourteen million, four hundred sixty-seven thousand, five hundred fifty-seven".