661090979 has 2 divisors, whose sum is σ = 661090980. Its totient is φ = 661090978.

The previous prime is 661090973. The next prime is 661090981. The reversal of 661090979 is 979090166.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661090979 - 2¹² = 661086883 is a prime.

Together with 661090981, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661090973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330545489 + 330545490.

It is an arithmetic number, because the mean of its divisors is an integer number (330545490).

Almost surely, 2^661090979 is an apocalyptic number.

661090979 is a deficient number, since it is larger than the sum of its proper divisors (1).

661090979 is an equidigital number, since it uses as much as digits as its factorization.

661090979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 183708, while the sum is 47.

The square root of 661090979 is about 25711.6895399738. The cubic root of 661090979 is about 871.1382375695.

The spelling of 661090979 in words is "six hundred sixty-one million, ninety thousand, nine hundred seventy-nine".