1381921 has 2 divisors, whose sum is σ = 1381922. Its totient is φ = 1381920.

The previous prime is 1381907. The next prime is 1381967. The reversal of 1381921 is 1291831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1380625 + 1296 = 1175^2 + 36^2 .

It is an emirp because it is prime and its reverse (1291831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1381921 - 2⁹ = 1381409 is a prime.

It is not a weakly prime, because it can be changed into another prime (1381901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 690960 + 690961.

It is an arithmetic number, because the mean of its divisors is an integer number (690961).

2^1381921 is an apocalyptic number.

It is an amenable number.

1381921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381921 is an equidigital number, since it uses as much as digits as its factorization.

1381921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 25.

The square root of 1381921 is about 1175.5513600009. The cubic root of 1381921 is about 111.3852640791.

The spelling of 1381921 in words is "one million, three hundred eighty-one thousand, nine hundred twenty-one".