661090597 has 2 divisors, whose sum is σ = 661090598. Its totient is φ = 661090596.

The previous prime is 661090513. The next prime is 661090627. The reversal of 661090597 is 795090166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 471367521 + 189723076 = 21711^2 + 13774^2 .

It is a cyclic number.

It is not a de Polignac number, because 661090597 - 2²³ = 652701989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665090597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330545298 + 330545299.

It is an arithmetic number, because the mean of its divisors is an integer number (330545299).

Almost surely, 2^661090597 is an apocalyptic number.

It is an amenable number.

661090597 is a deficient number, since it is larger than the sum of its proper divisors (1).

661090597 is an equidigital number, since it uses as much as digits as its factorization.

661090597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 102060, while the sum is 43.

The square root of 661090597 is about 25711.6821114450. The cubic root of 661090597 is about 871.1380697787.

The spelling of 661090597 in words is "six hundred sixty-one million, ninety thousand, five hundred ninety-seven".