20388725138 has 4 divisors (see below), whose sum is σ = 30583087710. Its totient is φ = 10194362568.

The previous prime is 20388725117. The next prime is 20388725183. The reversal of 20388725138 is 83152788302.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12932920729 + 7455804409 = 113723^2 + 86347^2 .

It is a super-2 number, since 2×20388725138² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20388725092 and 20388725101.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5097181283 + ... + 5097181286.

Almost surely, 2^20388725138 is an apocalyptic number.

20388725138 is a deficient number, since it is larger than the sum of its proper divisors (10194362572).

20388725138 is a wasteful number, since it uses less digits than its factorization.

20388725138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10194362571.

The product of its (nonzero) digits is 645120, while the sum is 47.

The spelling of 20388725138 in words is "twenty billion, three hundred eighty-eight million, seven hundred twenty-five thousand, one hundred thirty-eight".