90102121 has 4 divisors (see below), whose sum is σ = 90125892. Its totient is φ = 90078352.

The previous prime is 90102119. The next prime is 90102137. The reversal of 90102121 is 12120109.

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 5664400 + 84437721 = 2380^2 + 9189^2 .

It is a cyclic number.

It is not a de Polignac number, because 90102121 - 2¹ = 90102119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 90102095 and 90102104.

It is not an unprimeable number, because it can be changed into a prime (90102721) 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, 4786 + ... + 14251.

It is an arithmetic number, because the mean of its divisors is an integer number (22531473).

Almost surely, 2^90102121 is an apocalyptic number.

It is an amenable number.

90102121 is a deficient number, since it is larger than the sum of its proper divisors (23771).

90102121 is a wasteful number, since it uses less digits than its factorization.

90102121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23770.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 90102121 is about 9492.2137038733. The cubic root of 90102121 is about 448.3099089334.

The spelling of 90102121 in words is "ninety million, one hundred two thousand, one hundred twenty-one".