91669909 has 2 divisors, whose sum is σ = 91669910. Its totient is φ = 91669908.

The previous prime is 91669861. The next prime is 91669943. The reversal of 91669909 is 90996619.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64400625 + 27269284 = 8025^2 + 5222^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91669909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91669999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45834954 + 45834955.

It is an arithmetic number, because the mean of its divisors is an integer number (45834955).

Almost surely, 2^91669909 is an apocalyptic number.

It is an amenable number.

91669909 is a deficient number, since it is larger than the sum of its proper divisors (1).

91669909 is an equidigital number, since it uses as much as digits as its factorization.

91669909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 236196, while the sum is 49.

The square root of 91669909 is about 9574.4404014021. The cubic root of 91669909 is about 450.8951875647.

The spelling of 91669909 in words is "ninety-one million, six hundred sixty-nine thousand, nine hundred nine".