661091677 has 2 divisors, whose sum is σ = 661091678. Its totient is φ = 661091676.

The previous prime is 661091623. The next prime is 661091713. The reversal of 661091677 is 776190166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 611375076 + 49716601 = 24726^2 + 7051^2 .

It is a cyclic number.

It is not a de Polignac number, because 661091677 - 2⁷ = 661091549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661091477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330545838 + 330545839.

It is an arithmetic number, because the mean of its divisors is an integer number (330545839).

Almost surely, 2^661091677 is an apocalyptic number.

It is an amenable number.

661091677 is a deficient number, since it is larger than the sum of its proper divisors (1).

661091677 is an equidigital number, since it uses as much as digits as its factorization.

661091677 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 95256, while the sum is 43.

The square root of 661091677 is about 25711.7031135629. The cubic root of 661091677 is about 871.1385441608.

The spelling of 661091677 in words is "six hundred sixty-one million, ninety-one thousand, six hundred seventy-seven".