981138999 has 8 divisors (see below), whose sum is σ = 1324744960. Its totient is φ = 645812856.

The previous prime is 981138973. The next prime is 981139007. The reversal of 981138999 is 999831189.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 981138999 - 2¹¹ = 981136951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (981138919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2069677 + ... + 2070150.

It is an arithmetic number, because the mean of its divisors is an integer number (165593120).

Almost surely, 2^981138999 is an apocalyptic number.

981138999 is a deficient number, since it is larger than the sum of its proper divisors (343605961).

981138999 is a wasteful number, since it uses less digits than its factorization.

981138999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4139909.

The product of its digits is 1259712, while the sum is 57.

The square root of 981138999 is about 31323.1383963996. The cubic root of 981138999 is about 993.6730538421.

The spelling of 981138999 in words is "nine hundred eighty-one million, one hundred thirty-eight thousand, nine hundred ninety-nine".