90691817 has 2 divisors, whose sum is σ = 90691818. Its totient is φ = 90691816.

The previous prime is 90691793. The next prime is 90691819. The reversal of 90691817 is 71819609.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73085401 + 17606416 = 8549^2 + 4196^2 .

It is an emirp because it is prime and its reverse (71819609) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90691817 - 2¹² = 90687721 is a prime.

It is a super-2 number, since 2×90691817² = 16450011341522978, which contains 22 as substring.

Together with 90691819, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (90691819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45345908 + 45345909.

It is an arithmetic number, because the mean of its divisors is an integer number (45345909).

Almost surely, 2^90691817 is an apocalyptic number.

It is an amenable number.

90691817 is a deficient number, since it is larger than the sum of its proper divisors (1).

90691817 is an equidigital number, since it uses as much as digits as its factorization.

90691817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 90691817 is about 9523.2251364756. The cubic root of 90691817 is about 449.2858086762.

The spelling of 90691817 in words is "ninety million, six hundred ninety-one thousand, eight hundred seventeen".