1981696 has 18 divisors (see below), whose sum is σ = 3956162. Its totient is φ = 990720.

The previous prime is 1981691. The next prime is 1981699. The reversal of 1981696 is 6961891.

It can be written as a sum of positive squares in only one way, i.e., 1440000 + 541696 = 1200^2 + 736^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3615 + ... + 4126.

2^1981696 is an apocalyptic number.

1981696 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1981696 is a deficient number, since it is larger than the sum of its proper divisors (1974466).

1981696 is an frugal number, since it uses more digits than its factorization.

1981696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7757 (or 7743 counting only the distinct ones).

The product of its digits is 23328, while the sum is 40.

The square root of 1981696 is about 1407.7272463087. The cubic root of 1981696 is about 125.6065665221.

The spelling of 1981696 in words is "one million, nine hundred eighty-one thousand, six hundred ninety-six".