661472857957 has 2 divisors, whose sum is σ = 661472857958. Its totient is φ = 661472857956.

The previous prime is 661472857949. The next prime is 661472857979. The reversal of 661472857957 is 759758274166.

661472857957 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., 626399434116 + 35073423841 = 791454^2 + 187279^2 .

It is a cyclic number.

It is not a de Polignac number, because 661472857957 - 2³ = 661472857949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661472857892 and 661472857901.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661472857987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330736428978 + 330736428979.

It is an arithmetic number, because the mean of its divisors is an integer number (330736428979).

Almost surely, 2^661472857957 is an apocalyptic number.

It is an amenable number.

661472857957 is a deficient number, since it is larger than the sum of its proper divisors (1).

661472857957 is an equidigital number, since it uses as much as digits as its factorization.

661472857957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 177811200, while the sum is 67.

The spelling of 661472857957 in words is "six hundred sixty-one billion, four hundred seventy-two million, eight hundred fifty-seven thousand, nine hundred fifty-seven".