90722218 has 4 divisors (see below), whose sum is σ = 136083330. Its totient is φ = 45361108.

The previous prime is 90722147. The next prime is 90722227. The reversal of 90722218 is 81222709.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81222709 = 6397 ⋅12697.

It can be written as a sum of positive squares in only one way, i.e., 70174129 + 20548089 = 8377^2 + 4533^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 90722218.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22680553 + ... + 22680556.

Almost surely, 2^90722218 is an apocalyptic number.

90722218 is a deficient number, since it is larger than the sum of its proper divisors (45361112).

90722218 is a wasteful number, since it uses less digits than its factorization.

90722218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45361111.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 90722218 is about 9524.8211531766. The cubic root of 90722218 is about 449.3360050902.

It can be divided in two parts, 907 and 22218, that multiplied together give a triangular number (20151726 = T₆₃₄₈).

The spelling of 90722218 in words is "ninety million, seven hundred twenty-two thousand, two hundred eighteen".