91945409 has 2 divisors, whose sum is σ = 91945410. Its totient is φ = 91945408.

The previous prime is 91945397. The next prime is 91945417. The reversal of 91945409 is 90454919.

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., 90307009 + 1638400 = 9503^2 + 1280^2 .

It is a cyclic number.

It is not a de Polignac number, because 91945409 - 2⁸ = 91945153 is a prime.

It is not a weakly prime, because it can be changed into another prime (91945429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45972704 + 45972705.

It is an arithmetic number, because the mean of its divisors is an integer number (45972705).

Almost surely, 2^91945409 is an apocalyptic number.

It is an amenable number.

91945409 is a deficient number, since it is larger than the sum of its proper divisors (1).

91945409 is an equidigital number, since it uses as much as digits as its factorization.

91945409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 58320, while the sum is 41.

The square root of 91945409 is about 9588.8168717522. The cubic root of 91945409 is about 451.3464348345.

The spelling of 91945409 in words is "ninety-one million, nine hundred forty-five thousand, four hundred nine".