2138406681 has 16 divisors (see below), whose sum is σ = 2892296960. Its totient is φ = 1405123200.

The previous prime is 2138406653. The next prime is 2138406703. The reversal of 2138406681 is 1866048312.

It is not a de Polignac number, because 2138406681 - 2⁹ = 2138406169 is a prime.

It is a super-2 number, since 2×2138406681² = 9145566266690871522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2138406181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134931 + ... + 149943.

It is an arithmetic number, because the mean of its divisors is an integer number (180768560).

Almost surely, 2^2138406681 is an apocalyptic number.

It is an amenable number.

2138406681 is a deficient number, since it is larger than the sum of its proper divisors (753890279).

2138406681 is a wasteful number, since it uses less digits than its factorization.

2138406681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15696.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 2138406681 is about 46242.9095213526. The cubic root of 2138406681 is about 1288.3388431270.

The spelling of 2138406681 in words is "two billion, one hundred thirty-eight million, four hundred six thousand, six hundred eighty-one".