90123281 has 2 divisors, whose sum is σ = 90123282. Its totient is φ = 90123280.

The previous prime is 90123277. The next prime is 90123283. The reversal of 90123281 is 18232109.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80263681 + 9859600 = 8959^2 + 3140^2 .

It is a cyclic number.

It is not a de Polignac number, because 90123281 - 2² = 90123277 is a prime.

It is a super-2 number, since 2×90123281² = 16244411556409922, which contains 22 as substring.

Together with 90123283, it forms a pair of twin primes.

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 90123281.

It is not a weakly prime, because it can be changed into another prime (90123283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45061640 + 45061641.

It is an arithmetic number, because the mean of its divisors is an integer number (45061641).

Almost surely, 2^90123281 is an apocalyptic number.

It is an amenable number.

90123281 is a deficient number, since it is larger than the sum of its proper divisors (1).

90123281 is an equidigital number, since it uses as much as digits as its factorization.

90123281 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 90123281 is about 9493.3282361878. The cubic root of 90123281 is about 448.3450005793.

The spelling of 90123281 in words is "ninety million, one hundred twenty-three thousand, two hundred eighty-one".