20121021138 has 32 divisors (see below), whose sum is σ = 43346276352. Its totient is φ = 6208448400.

The previous prime is 20121021101. The next prime is 20121021139. The reversal of 20121021138 is 83112012102.

20121021138 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (20121021139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2347408 + ... + 2355963.

It is an arithmetic number, because the mean of its divisors is an integer number (1354571136).

Almost surely, 2^20121021138 is an apocalyptic number.

20121021138 is an abundant number, since it is smaller than the sum of its proper divisors (23225255214).

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

20121021138 is a wasteful number, since it uses less digits than its factorization.

20121021138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4703430.

The product of its (nonzero) digits is 192, while the sum is 21.

The spelling of 20121021138 in words is "twenty billion, one hundred twenty-one million, twenty-one thousand, one hundred thirty-eight".