661961059 has 2 divisors, whose sum is σ = 661961060. Its totient is φ = 661961058.

The previous prime is 661961023. The next prime is 661961063. The reversal of 661961059 is 950169166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661961059 - 2¹³ = 661952867 is a prime.

It is not a weakly prime, because it can be changed into another prime (661961009) 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, 330980529 + 330980530.

It is an arithmetic number, because the mean of its divisors is an integer number (330980530).

Almost surely, 2^661961059 is an apocalyptic number.

661961059 is a deficient number, since it is larger than the sum of its proper divisors (1).

661961059 is an equidigital number, since it uses as much as digits as its factorization.

661961059 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 43.

The square root of 661961059 is about 25728.6039069360. The cubic root of 661961059 is about 871.5202463503.

The spelling of 661961059 in words is "six hundred sixty-one million, nine hundred sixty-one thousand, fifty-nine".