90128231 has 2 divisors, whose sum is σ = 90128232. Its totient is φ = 90128230.

The previous prime is 90128197. The next prime is 90128239. The reversal of 90128231 is 13282109.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90128231 is a prime.

It is a super-2 number, since 2×90128231² = 16246196046378722, 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 90128231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90128239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45064115 + 45064116.

It is an arithmetic number, because the mean of its divisors is an integer number (45064116).

Almost surely, 2^90128231 is an apocalyptic number.

90128231 is a deficient number, since it is larger than the sum of its proper divisors (1).

90128231 is an equidigital number, since it uses as much as digits as its factorization.

90128231 is an odious number, because the sum of its binary digits is odd.

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

The square root of 90128231 is about 9493.5889420177. The cubic root of 90128231 is about 448.3532088436.

The spelling of 90128231 in words is "ninety million, one hundred twenty-eight thousand, two hundred thirty-one".