1981138 has 8 divisors (see below), whose sum is σ = 2977920. Its totient is φ = 988500.

The previous prime is 1981099. The next prime is 1981141. The reversal of 1981138 is 8311891.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 843 + ... + 2161.

It is an arithmetic number, because the mean of its divisors is an integer number (372240).

2^1981138 is an apocalyptic number.

1981138 is a deficient number, since it is larger than the sum of its proper divisors (996782).

1981138 is a wasteful number, since it uses less digits than its factorization.

1981138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2072.

The product of its digits is 1728, while the sum is 31.

The square root of 1981138 is about 1407.5290405530. The cubic root of 1981138 is about 125.5947761090.

The spelling of 1981138 in words is "one million, nine hundred eighty-one thousand, one hundred thirty-eight".