1981944 has 24 divisors (see below), whose sum is σ = 5367960. Its totient is φ = 660624.

The previous prime is 1981939. The next prime is 1981949. The reversal of 1981944 is 4491891.

It is an interprime number because it is at equal distance from previous prime (1981939) and next prime (1981949).

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 1981899 and 1981908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981949) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13692 + ... + 13835.

It is an arithmetic number, because the mean of its divisors is an integer number (223665).

2^1981944 is an apocalyptic number.

It is an amenable number.

1981944 is an abundant number, since it is smaller than the sum of its proper divisors (3386016).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1981944 is a wasteful number, since it uses less digits than its factorization.

1981944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27539 (or 27532 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 1981944 is about 1407.8153287985. The cubic root of 1981944 is about 125.6118059953.

The spelling of 1981944 in words is "one million, nine hundred eighty-one thousand, nine hundred forty-four".