91372009 has 2 divisors, whose sum is σ = 91372010. Its totient is φ = 91372008.

The previous prime is 91372003. The next prime is 91372019. The reversal of 91372009 is 90027319.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91298025 + 73984 = 9555^2 + 272^2 .

It is an emirp because it is prime and its reverse (90027319) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91372009 - 2⁷ = 91371881 is a prime.

It is not a weakly prime, because it can be changed into another prime (91372003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45686004 + 45686005.

It is an arithmetic number, because the mean of its divisors is an integer number (45686005).

Almost surely, 2^91372009 is an apocalyptic number.

It is an amenable number.

91372009 is a deficient number, since it is larger than the sum of its proper divisors (1).

91372009 is an equidigital number, since it uses as much as digits as its factorization.

91372009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 91372009 is about 9558.8706968972. The cubic root of 91372009 is about 450.4062323450.

It can be divided in two parts, 91 and 372009, that added together give a square (372100 = 610²).

The spelling of 91372009 in words is "ninety-one million, three hundred seventy-two thousand, nine".