90638689 has 2 divisors, whose sum is σ = 90638690. Its totient is φ = 90638688.

The previous prime is 90638687. The next prime is 90638693. The reversal of 90638689 is 98683609.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77440000 + 13198689 = 8800^2 + 3633^2 .

It is an emirp because it is prime and its reverse (98683609) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90638689 - 2¹ = 90638687 is a prime.

Together with 90638687, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (90638687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45319344 + 45319345.

It is an arithmetic number, because the mean of its divisors is an integer number (45319345).

Almost surely, 2^90638689 is an apocalyptic number.

It is an amenable number.

90638689 is a deficient number, since it is larger than the sum of its proper divisors (1).

90638689 is an equidigital number, since it uses as much as digits as its factorization.

90638689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 90638689 is about 9520.4353366850. The cubic root of 90638689 is about 449.1980597857.

The spelling of 90638689 in words is "ninety million, six hundred thirty-eight thousand, six hundred eighty-nine".