90100120021 has 4 divisors (see below), whose sum is σ = 90101250700. Its totient is φ = 90098989344.

The previous prime is 90100119971. The next prime is 90100120027. The reversal of 90100120021 is 12002100109.

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 16599487921 + 73500632100 = 128839^2 + 271110^2 .

It is a cyclic number.

It is not a de Polignac number, because 90100120021 - 2²¹ = 90098022869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 90100119977 and 90100120004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90100120027) 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, 435936 + ... + 608473.

It is an arithmetic number, because the mean of its divisors is an integer number (22525312675).

Almost surely, 2^90100120021 is an apocalyptic number.

It is an amenable number.

90100120021 is a deficient number, since it is larger than the sum of its proper divisors (1130679).

90100120021 is a wasteful number, since it uses less digits than its factorization.

90100120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1130678.

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

The spelling of 90100120021 in words is "ninety billion, one hundred million, one hundred twenty thousand, twenty-one".