1381631 has 4 divisors (see below), whose sum is σ = 1399200. Its totient is φ = 1364064.

The previous prime is 1381621. The next prime is 1381637. The reversal of 1381631 is 1361831.

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

It is a cyclic number.

It is not a de Polignac number, because 1381631 - 2¹⁰ = 1380607 is a prime.

It is a super-2 number, since 2×1381631² = 3817808440322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1381597 and 1381606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8666 + ... + 8823.

It is an arithmetic number, because the mean of its divisors is an integer number (349800).

2^1381631 is an apocalyptic number.

1381631 is a deficient number, since it is larger than the sum of its proper divisors (17569).

1381631 is an equidigital number, since it uses as much as digits as its factorization.

1381631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17568.

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

The square root of 1381631 is about 1175.4280071531. The cubic root of 1381631 is about 111.3774720306.

The spelling of 1381631 in words is "one million, three hundred eighty-one thousand, six hundred thirty-one".