90218231 has 2 divisors, whose sum is σ = 90218232. Its totient is φ = 90218230.

The previous prime is 90218221. The next prime is 90218273. The reversal of 90218231 is 13281209.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 90218231 - 2¹⁰ = 90217207 is a prime.

It is a super-2 number, since 2×90218231² = 16278658409538722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 90218231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90218221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45109115 + 45109116.

It is an arithmetic number, because the mean of its divisors is an integer number (45109116).

Almost surely, 2^90218231 is an apocalyptic number.

90218231 is a deficient number, since it is larger than the sum of its proper divisors (1).

90218231 is an equidigital number, since it uses as much as digits as its factorization.

90218231 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 90218231 is about 9498.3278001973. The cubic root of 90218231 is about 448.5023976321.

The spelling of 90218231 in words is "ninety million, two hundred eighteen thousand, two hundred thirty-one".