1331681 has 4 divisors (see below), whose sum is σ = 1434132. Its totient is φ = 1229232.

The previous prime is 1331663. The next prime is 1331683. The reversal of 1331681 is 1861331.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 819025 + 512656 = 905^2 + 716^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331681 - 2¹⁴ = 1315297 is a prime.

It is a super-2 number, since 2×1331681² = 3546748571522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1331683) 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, 51206 + ... + 51231.

It is an arithmetic number, because the mean of its divisors is an integer number (358533).

2^1331681 is an apocalyptic number.

It is an amenable number.

1331681 is a deficient number, since it is larger than the sum of its proper divisors (102451).

1331681 is a wasteful number, since it uses less digits than its factorization.

1331681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102450.

The product of its digits is 432, while the sum is 23.

The square root of 1331681 is about 1153.9848352556. The cubic root of 1331681 is about 110.0187571319.

The spelling of 1331681 in words is "one million, three hundred thirty-one thousand, six hundred eighty-one".