661180789 has 2 divisors, whose sum is σ = 661180790. Its totient is φ = 661180788.

The previous prime is 661180757. The next prime is 661180799. The reversal of 661180789 is 987081166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 458687889 + 202492900 = 21417^2 + 14230^2 .

It is a cyclic number.

It is not a de Polignac number, because 661180789 - 2⁵ = 661180757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661180799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330590394 + 330590395.

It is an arithmetic number, because the mean of its divisors is an integer number (330590395).

Almost surely, 2^661180789 is an apocalyptic number.

It is an amenable number.

661180789 is a deficient number, since it is larger than the sum of its proper divisors (1).

661180789 is an equidigital number, since it uses as much as digits as its factorization.

661180789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 661180789 is about 25713.4359625469. The cubic root of 661180789 is about 871.1776841737.

The spelling of 661180789 in words is "six hundred sixty-one million, one hundred eighty thousand, seven hundred eighty-nine".