1981899 has 18 divisors (see below), whose sum is σ = 2956668. Its totient is φ = 1279200.

The previous prime is 1981891. The next prime is 1981901. The reversal of 1981899 is 9981891.

It is not a de Polignac number, because 1981899 - 2³ = 1981891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1981891) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 15064 + ... + 15194.

2^1981899 is an apocalyptic number.

1981899 is a deficient number, since it is larger than the sum of its proper divisors (974769).

1981899 is a wasteful number, since it uses less digits than its factorization.

1981899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 175 counting only the distinct ones).

The product of its digits is 46656, while the sum is 45.

The square root of 1981899 is about 1407.7993464979. The cubic root of 1981899 is about 125.6108553169.

It can be divided in two parts, 19 and 81899, that added together give a palindrome (81918).

The spelling of 1981899 in words is "one million, nine hundred eighty-one thousand, eight hundred ninety-nine".