90242221 has 2 divisors, whose sum is σ = 90242222. Its totient is φ = 90242220.

The previous prime is 90242219. The next prime is 90242227. The reversal of 90242221 is 12224209.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49154121 + 41088100 = 7011^2 + 6410^2 .

It is an emirp because it is prime and its reverse (12224209) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90242221 - 2¹ = 90242219 is a prime.

Together with 90242219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 90242192 and 90242201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90242227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45121110 + 45121111.

It is an arithmetic number, because the mean of its divisors is an integer number (45121111).

Almost surely, 2^90242221 is an apocalyptic number.

It is an amenable number.

90242221 is a deficient number, since it is larger than the sum of its proper divisors (1).

90242221 is an equidigital number, since it uses as much as digits as its factorization.

90242221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 90242221 is about 9499.5905701246. The cubic root of 90242221 is about 448.5421479828.

The spelling of 90242221 in words is "ninety million, two hundred forty-two thousand, two hundred twenty-one".