90221028218 has 4 divisors (see below), whose sum is σ = 135331542330. Its totient is φ = 45110514108.

The previous prime is 90221028143. The next prime is 90221028229. The reversal of 90221028218 is 81282012209.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81282012209 = 433 ⋅187718273.

It can be written as a sum of positive squares in only one way, i.e., 80113339849 + 10107688369 = 283043^2 + 100537^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22555257053 + ... + 22555257056.

Almost surely, 2^90221028218 is an apocalyptic number.

90221028218 is a deficient number, since it is larger than the sum of its proper divisors (45110514112).

90221028218 is a wasteful number, since it uses less digits than its factorization.

90221028218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45110514111.

The product of its (nonzero) digits is 9216, while the sum is 35.

The spelling of 90221028218 in words is "ninety billion, two hundred twenty-one million, twenty-eight thousand, two hundred eighteen".