661096091 has 2 divisors, whose sum is σ = 661096092. Its totient is φ = 661096090.

The previous prime is 661096069. The next prime is 661096157. The reversal of 661096091 is 190690166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661096091 - 2¹⁸ = 660833947 is a prime.

It is not a weakly prime, because it can be changed into another prime (661006091) 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, 330548045 + 330548046.

It is an arithmetic number, because the mean of its divisors is an integer number (330548046).

Almost surely, 2^661096091 is an apocalyptic number.

661096091 is a deficient number, since it is larger than the sum of its proper divisors (1).

661096091 is an equidigital number, since it uses as much as digits as its factorization.

661096091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 661096091 is about 25711.7889498183. The cubic root of 661096091 is about 871.1404829726.

The spelling of 661096091 in words is "six hundred sixty-one million, ninety-six thousand, ninety-one".