661357775473 has 2 divisors, whose sum is σ = 661357775474. Its totient is φ = 661357775472.

The previous prime is 661357775467. The next prime is 661357775587. The reversal of 661357775473 is 374577753166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 594923743969 + 66434031504 = 771313^2 + 257748^2 .

It is a cyclic number.

It is not a de Polignac number, because 661357775473 - 2¹⁷ = 661357644401 is a prime.

It is not a weakly prime, because it can be changed into another prime (661357775873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330678887736 + 330678887737.

It is an arithmetic number, because the mean of its divisors is an integer number (330678887737).

Almost surely, 2^661357775473 is an apocalyptic number.

It is an amenable number.

661357775473 is a deficient number, since it is larger than the sum of its proper divisors (1).

661357775473 is an equidigital number, since it uses as much as digits as its factorization.

661357775473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77792400, while the sum is 61.

The spelling of 661357775473 in words is "six hundred sixty-one billion, three hundred fifty-seven million, seven hundred seventy-five thousand, four hundred seventy-three".