1138786821 has 12 divisors (see below), whose sum is σ = 1668083040. Its totient is φ = 748497960.

The previous prime is 1138786813. The next prime is 1138786841. The reversal of 1138786821 is 1286878311.

It is a happy number.

It is not a de Polignac number, because 1138786821 - 2³ = 1138786813 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1138786841) 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, 890431 + ... + 891708.

It is an arithmetic number, because the mean of its divisors is an integer number (139006920).

Almost surely, 2^1138786821 is an apocalyptic number.

It is an amenable number.

1138786821 is a deficient number, since it is larger than the sum of its proper divisors (529296219).

1138786821 is a wasteful number, since it uses less digits than its factorization.

1138786821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1782216 (or 1782213 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 1138786821 is about 33745.9156195235. The cubic root of 1138786821 is about 1044.2732280197.

The spelling of 1138786821 in words is "one billion, one hundred thirty-eight million, seven hundred eighty-six thousand, eight hundred twenty-one".