1138888891 has 4 divisors (see below), whose sum is σ = 1301587312. Its totient is φ = 976190472.

The previous prime is 1138888889. The next prime is 1138888901. The reversal of 1138888891 is 1988888311.

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

It is a cyclic number.

It is not a de Polignac number, because 1138888891 - 2¹ = 1138888889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1138888591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81349200 + ... + 81349213.

It is an arithmetic number, because the mean of its divisors is an integer number (325396828).

Almost surely, 2^1138888891 is an apocalyptic number.

1138888891 is a deficient number, since it is larger than the sum of its proper divisors (162698421).

1138888891 is an equidigital number, since it uses as much as digits as its factorization.

1138888891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162698420.

The product of its digits is 884736, while the sum is 55.

The square root of 1138888891 is about 33747.4279168057. The cubic root of 1138888891 is about 1044.3044266550.

The spelling of 1138888891 in words is "one billion, one hundred thirty-eight million, eight hundred eighty-eight thousand, eight hundred ninety-one".