1391861 has 2 divisors, whose sum is σ = 1391862. Its totient is φ = 1391860.

The previous prime is 1391849. The next prime is 1391893. The reversal of 1391861 is 1681931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1380625 + 11236 = 1175^2 + 106^2 .

It is an emirp because it is prime and its reverse (1681931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1391861 - 2¹⁸ = 1129717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1391261) 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 as a sum of consecutive naturals, namely, 695930 + 695931.

It is an arithmetic number, because the mean of its divisors is an integer number (695931).

2^1391861 is an apocalyptic number.

It is an amenable number.

1391861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391861 is an equidigital number, since it uses as much as digits as its factorization.

1391861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 29.

The square root of 1391861 is about 1179.7715880627. The cubic root of 1391861 is about 111.6516868102.

The spelling of 1391861 in words is "one million, three hundred ninety-one thousand, eight hundred sixty-one".