20121090138 has 24 divisors (see below), whose sum is σ = 45491161248. Its totient is φ = 6415419912.

The previous prime is 20121090137. The next prime is 20121090149. The reversal of 20121090138 is 83109012102.

It is not an unprimeable number, because it can be changed into a prime (20121090137) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24300420 + ... + 24301247.

It is an arithmetic number, because the mean of its divisors is an integer number (1895465052).

Almost surely, 2^20121090138 is an apocalyptic number.

20121090138 is an abundant number, since it is smaller than the sum of its proper divisors (25370071110).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20121090138 is a wasteful number, since it uses less digits than its factorization.

20121090138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48601698 (or 48601695 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The spelling of 20121090138 in words is "twenty billion, one hundred twenty-one million, ninety thousand, one hundred thirty-eight".