90605681 has 2 divisors, whose sum is σ = 90605682. Its totient is φ = 90605680.

The previous prime is 90605677. The next prime is 90605689. The reversal of 90605681 is 18650609.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48874081 + 41731600 = 6991^2 + 6460^2 .

It is a cyclic number.

It is not a de Polignac number, because 90605681 - 2² = 90605677 is a prime.

It is a super-2 number, since 2×90605681² = 16418778858947522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (90605689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45302840 + 45302841.

It is an arithmetic number, because the mean of its divisors is an integer number (45302841).

Almost surely, 2^90605681 is an apocalyptic number.

It is an amenable number.

90605681 is a deficient number, since it is larger than the sum of its proper divisors (1).

90605681 is an equidigital number, since it uses as much as digits as its factorization.

90605681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 90605681 is about 9518.7016446572. The cubic root of 90605681 is about 449.1435248332.

It can be divided in two parts, 9060 and 5681, that added together give a palindrome (14741).

The spelling of 90605681 in words is "ninety million, six hundred five thousand, six hundred eighty-one".