1981373 has 4 divisors (see below), whose sum is σ = 1984320. Its totient is φ = 1978428.

The previous prime is 1981361. The next prime is 1981393. The reversal of 1981373 is 3731891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3731891 = 17 ⋅219523.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981373 is a prime.

It is a super-3 number, since 3×1981373³ = 23335653983563626351, which contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981393) 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, 86 + ... + 1992.

It is an arithmetic number, because the mean of its divisors is an integer number (496080).

2^1981373 is an apocalyptic number.

It is an amenable number.

1981373 is a deficient number, since it is larger than the sum of its proper divisors (2947).

1981373 is a wasteful number, since it uses less digits than its factorization.

1981373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2946.

The product of its digits is 4536, while the sum is 32.

The square root of 1981373 is about 1407.6125177051. The cubic root of 1981373 is about 125.5997418754.

The spelling of 1981373 in words is "one million, nine hundred eighty-one thousand, three hundred seventy-three".