1381681 has 4 divisors (see below), whose sum is σ = 1579072. Its totient is φ = 1184292.

The previous prime is 1381649. The next prime is 1381693. The reversal of 1381681 is 1861831.

It is a happy number.

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 1381681 - 2⁵ = 1381649 is a prime.

It is a super-2 number, since 2×1381681² = 3818084771522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1381621) 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, 98685 + ... + 98698.

It is an arithmetic number, because the mean of its divisors is an integer number (394768).

2^1381681 is an apocalyptic number.

It is an amenable number.

1381681 is a deficient number, since it is larger than the sum of its proper divisors (197391).

1381681 is an equidigital number, since it uses as much as digits as its factorization.

1381681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197390.

The product of its digits is 1152, while the sum is 28.

The square root of 1381681 is about 1175.4492758090. The cubic root of 1381681 is about 111.3788155650.

The spelling of 1381681 in words is "one million, three hundred eighty-one thousand, six hundred eighty-one".