90086021 has 2 divisors, whose sum is σ = 90086022. Its totient is φ = 90086020.

The previous prime is 90085997. The next prime is 90086023. The reversal of 90086021 is 12068009.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90060100 + 25921 = 9490^2 + 161^2 .

It is an emirp because it is prime and its reverse (12068009) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90086021 is a prime.

It is a super-2 number, since 2×90086021² = 16230982359224882, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 90086023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90086023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45043010 + 45043011.

It is an arithmetic number, because the mean of its divisors is an integer number (45043011).

Almost surely, 2^90086021 is an apocalyptic number.

It is an amenable number.

90086021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90086021 is an equidigital number, since it uses as much as digits as its factorization.

90086021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 90086021 is about 9491.3656024831. The cubic root of 90086021 is about 448.2832050874.

The spelling of 90086021 in words is "ninety million, eighty-six thousand, twenty-one".