2139768121 has 4 divisors (see below), whose sum is σ = 2265636852. Its totient is φ = 2013899392.

The previous prime is 2139768119. The next prime is 2139768133. The reversal of 2139768121 is 1218679312.

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 1856317225 + 283450896 = 43085^2 + 16836^2 .

It is a cyclic number.

It is not a de Polignac number, because 2139768121 - 2¹ = 2139768119 is a prime.

It is a super-2 number, since 2×2139768121² = 9157215223295741282, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2139768101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62934340 + ... + 62934373.

It is an arithmetic number, because the mean of its divisors is an integer number (566409213).

Almost surely, 2^2139768121 is an apocalyptic number.

It is an amenable number.

2139768121 is a deficient number, since it is larger than the sum of its proper divisors (125868731).

2139768121 is a wasteful number, since it uses less digits than its factorization.

2139768121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125868730.

The product of its digits is 36288, while the sum is 40.

The square root of 2139768121 is about 46257.6277061416. The cubic root of 2139768121 is about 1288.6121967954.

The spelling of 2139768121 in words is "two billion, one hundred thirty-nine million, seven hundred sixty-eight thousand, one hundred twenty-one".