1391641 has 2 divisors, whose sum is σ = 1391642. Its totient is φ = 1391640.

The previous prime is 1391629. The next prime is 1391647. The reversal of 1391641 is 1461931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1390041 + 1600 = 1179^2 + 40^2 .

It is an emirp because it is prime and its reverse (1461931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1391641 - 2⁹ = 1391129 is a prime.

1391641 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1391647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695820 + 695821.

It is an arithmetic number, because the mean of its divisors is an integer number (695821).

2^1391641 is an apocalyptic number.

It is an amenable number.

1391641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391641 is an equidigital number, since it uses as much as digits as its factorization.

1391641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 1391641 is about 1179.6783459910. The cubic root of 1391641 is about 111.6458038795.

The spelling of 1391641 in words is "one million, three hundred ninety-one thousand, six hundred forty-one".