661118573 has 2 divisors, whose sum is σ = 661118574. Its totient is φ = 661118572.

The previous prime is 661118569. The next prime is 661118599. The reversal of 661118573 is 375811166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 574944484 + 86174089 = 23978^2 + 9283^2 .

It is a cyclic number.

It is not a de Polignac number, because 661118573 - 2² = 661118569 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661118173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330559286 + 330559287.

It is an arithmetic number, because the mean of its divisors is an integer number (330559287).

Almost surely, 2^661118573 is an apocalyptic number.

It is an amenable number.

661118573 is a deficient number, since it is larger than the sum of its proper divisors (1).

661118573 is an equidigital number, since it uses as much as digits as its factorization.

661118573 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 38.

The square root of 661118573 is about 25712.2261385513. The cubic root of 661118573 is about 871.1503578650.

The spelling of 661118573 in words is "six hundred sixty-one million, one hundred eighteen thousand, five hundred seventy-three".