90972121 has 4 divisors (see below), whose sum is σ = 91062244. Its totient is φ = 90882000.

The previous prime is 90972109. The next prime is 90972127. The reversal of 90972121 is 12127909.

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 21483225 + 69488896 = 4635^2 + 8336^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90972121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90972127) 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, 43530 + ... + 45571.

It is an arithmetic number, because the mean of its divisors is an integer number (22765561).

Almost surely, 2^90972121 is an apocalyptic number.

It is an amenable number.

90972121 is a deficient number, since it is larger than the sum of its proper divisors (90123).

90972121 is a wasteful number, since it uses less digits than its factorization.

90972121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90122.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 90972121 is about 9537.9306455856. The cubic root of 90972121 is about 449.7482064625.

The spelling of 90972121 in words is "ninety million, nine hundred seventy-two thousand, one hundred twenty-one".