91644894989 has 2 divisors, whose sum is σ = 91644894990. Its totient is φ = 91644894988.

The previous prime is 91644894983. The next prime is 91644895003. The reversal of 91644894989 is 98949844619.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61946232100 + 29698662889 = 248890^2 + 172333^2 .

It is a cyclic number.

It is not a de Polignac number, because 91644894989 - 2¹⁶ = 91644829453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91644894983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45822447494 + 45822447495.

It is an arithmetic number, because the mean of its divisors is an integer number (45822447495).

Almost surely, 2^91644894989 is an apocalyptic number.

It is an amenable number.

91644894989 is a deficient number, since it is larger than the sum of its proper divisors (1).

91644894989 is an equidigital number, since it uses as much as digits as its factorization.

91644894989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 161243136, while the sum is 71.

The spelling of 91644894989 in words is "ninety-one billion, six hundred forty-four million, eight hundred ninety-four thousand, nine hundred eighty-nine".