91568641 has 2 divisors, whose sum is σ = 91568642. Its totient is φ = 91568640.

The previous prime is 91568623. The next prime is 91568707. The reversal of 91568641 is 14686519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74995600 + 16573041 = 8660^2 + 4071^2 .

It is an emirp because it is prime and its reverse (14686519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91568641 - 2¹⁹ = 91044353 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 91568594 and 91568603.

It is not a weakly prime, because it can be changed into another prime (91568941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45784320 + 45784321.

It is an arithmetic number, because the mean of its divisors is an integer number (45784321).

Almost surely, 2^91568641 is an apocalyptic number.

It is an amenable number.

91568641 is a deficient number, since it is larger than the sum of its proper divisors (1).

91568641 is an equidigital number, since it uses as much as digits as its factorization.

91568641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 40.

The square root of 91568641 is about 9569.1504847609. The cubic root of 91568641 is about 450.7290913371.

The spelling of 91568641 in words is "ninety-one million, five hundred sixty-eight thousand, six hundred forty-one".