90909121 has 2 divisors, whose sum is σ = 90909122. Its totient is φ = 90909120.

The previous prime is 90909109. The next prime is 90909127. The reversal of 90909121 is 12190909.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70560000 + 20349121 = 8400^2 + 4511^2 .

It is an emirp because it is prime and its reverse (12190909) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90909121 - 2⁵ = 90909089 is a prime.

It is not a weakly prime, because it can be changed into another prime (90909127) 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, 45454560 + 45454561.

It is an arithmetic number, because the mean of its divisors is an integer number (45454561).

Almost surely, 2^90909121 is an apocalyptic number.

It is an amenable number.

90909121 is a deficient number, since it is larger than the sum of its proper divisors (1).

90909121 is an equidigital number, since it uses as much as digits as its factorization.

90909121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 90909121 is about 9534.6274704364. The cubic root of 90909121 is about 449.6443626334.

The spelling of 90909121 in words is "ninety million, nine hundred nine thousand, one hundred twenty-one".