91408913 has 2 divisors, whose sum is σ = 91408914. Its totient is φ = 91408912.

The previous prime is 91408909. The next prime is 91408931. The reversal of 91408913 is 31980419.

Together with next prime (91408931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 88491649 + 2917264 = 9407^2 + 1708^2 .

It is a cyclic number.

It is not a de Polignac number, because 91408913 - 2² = 91408909 is a prime.

It is not a weakly prime, because it can be changed into another prime (91408013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45704456 + 45704457.

It is an arithmetic number, because the mean of its divisors is an integer number (45704457).

Almost surely, 2^91408913 is an apocalyptic number.

It is an amenable number.

91408913 is a deficient number, since it is larger than the sum of its proper divisors (1).

91408913 is an equidigital number, since it uses as much as digits as its factorization.

91408913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 91408913 is about 9560.8008555769. The cubic root of 91408913 is about 450.4668619788.

The spelling of 91408913 in words is "ninety-one million, four hundred eight thousand, nine hundred thirteen".