90994518221 has 2 divisors, whose sum is σ = 90994518222. Its totient is φ = 90994518220.

The previous prime is 90994518217. The next prime is 90994518247. The reversal of 90994518221 is 12281549909.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54365917225 + 36628600996 = 233165^2 + 191386^2 .

It is a cyclic number.

It is not a de Polignac number, because 90994518221 - 2² = 90994518217 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 90994518221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90994518521) 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, 45497259110 + 45497259111.

It is an arithmetic number, because the mean of its divisors is an integer number (45497259111).

Almost surely, 2^90994518221 is an apocalyptic number.

It is an amenable number.

90994518221 is a deficient number, since it is larger than the sum of its proper divisors (1).

90994518221 is an equidigital number, since it uses as much as digits as its factorization.

90994518221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 466560, while the sum is 50.

The spelling of 90994518221 in words is "ninety billion, nine hundred ninety-four million, five hundred eighteen thousand, two hundred twenty-one".