90218081 has 4 divisors (see below), whose sum is σ = 92418564. Its totient is φ = 88017600.

The previous prime is 90218071. The next prime is 90218087. The reversal of 90218081 is 18081209.

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 28987456 + 61230625 = 5384^2 + 7825^2 .

It is a cyclic number.

It is not a de Polignac number, because 90218081 - 2²⁶ = 23109217 is a prime.

It is a super-2 number, since 2×90218081² = 16278604278645122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90218087) 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, 1100180 + ... + 1100261.

It is an arithmetic number, because the mean of its divisors is an integer number (23104641).

Almost surely, 2^90218081 is an apocalyptic number.

It is an amenable number.

90218081 is a deficient number, since it is larger than the sum of its proper divisors (2200483).

90218081 is a wasteful number, since it uses less digits than its factorization.

90218081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200482.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 90218081 is about 9498.3199040672. The cubic root of 90218081 is about 448.5021490667.

The spelling of 90218081 in words is "ninety million, two hundred eighteen thousand, eighty-one".