1939981 has 4 divisors (see below), whose sum is σ = 2024352. Its totient is φ = 1855612.

The previous prime is 1939969. The next prime is 1939999. The reversal of 1939981 is 1899391.

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.

It is a cyclic number.

It is not a de Polignac number, because 1939981 - 2¹¹ = 1937933 is a prime.

It is a super-2 number, since 2×1939981² = 7527052560722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1939901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42151 + ... + 42196.

It is an arithmetic number, because the mean of its divisors is an integer number (506088).

2^1939981 is an apocalyptic number.

1939981 is the 745-th centered heptagonal number.

It is an amenable number.

1939981 is a deficient number, since it is larger than the sum of its proper divisors (84371).

1939981 is an equidigital number, since it uses as much as digits as its factorization.

1939981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84370.

The product of its digits is 17496, while the sum is 40.

The square root of 1939981 is about 1392.8320070992. The cubic root of 1939981 is about 124.7189632871.

It can be divided in two parts, 19 and 39981, that added together give a square (40000 = 200²).

The spelling of 1939981 in words is "one million, nine hundred thirty-nine thousand, nine hundred eighty-one".