1381621 has 2 divisors, whose sum is σ = 1381622. Its totient is φ = 1381620.

The previous prime is 1381613. The next prime is 1381637. The reversal of 1381621 is 1261831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1240996 + 140625 = 1114^2 + 375^2 .

It is an emirp because it is prime and its reverse (1261831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1381621 - 2³ = 1381613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1381592 and 1381601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1381421) 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 as a sum of consecutive naturals, namely, 690810 + 690811.

It is an arithmetic number, because the mean of its divisors is an integer number (690811).

2^1381621 is an apocalyptic number.

It is an amenable number.

1381621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381621 is an equidigital number, since it uses as much as digits as its factorization.

1381621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 22.

The square root of 1381621 is about 1175.4237533758. The cubic root of 1381621 is about 111.3772033198.

It can be divided in two parts, 1381 and 621, that added together give a palindrome (2002).

The spelling of 1381621 in words is "one million, three hundred eighty-one thousand, six hundred twenty-one".