90217071221 has 4 divisors (see below), whose sum is σ = 90218153292. Its totient is φ = 90215989152.

The previous prime is 90217071209. The next prime is 90217071227. The reversal of 90217071221 is 12217071209.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47692444996 + 42524626225 = 218386^2 + 206215^2 .

It is a cyclic number.

It is not a de Polignac number, because 90217071221 - 2¹⁰ = 90217070197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90217071227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 404486 + ... + 586551.

It is an arithmetic number, because the mean of its divisors is an integer number (22554538323).

Almost surely, 2^90217071221 is an apocalyptic number.

It is an amenable number.

90217071221 is a deficient number, since it is larger than the sum of its proper divisors (1082071).

90217071221 is an equidigital number, since it uses as much as digits as its factorization.

90217071221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082070.

The product of its (nonzero) digits is 3528, while the sum is 32.

The spelling of 90217071221 in words is "ninety billion, two hundred seventeen million, seventy-one thousand, two hundred twenty-one".