1391866841 has 2 divisors, whose sum is σ = 1391866842. Its totient is φ = 1391866840.

The previous prime is 1391866771. The next prime is 1391866843. The reversal of 1391866841 is 1486681931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1354608025 + 37258816 = 36805^2 + 6104^2 .

It is a cyclic number.

It is not a de Polignac number, because 1391866841 - 2¹⁴ = 1391850457 is a prime.

Together with 1391866843, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1391866843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695933420 + 695933421.

It is an arithmetic number, because the mean of its divisors is an integer number (695933421).

Almost surely, 2^1391866841 is an apocalyptic number.

It is an amenable number.

1391866841 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391866841 is an equidigital number, since it uses as much as digits as its factorization.

1391866841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 47.

The square root of 1391866841 is about 37307.7316517636. The cubic root of 1391866841 is about 1116.5184299352.

The spelling of 1391866841 in words is "one billion, three hundred ninety-one million, eight hundred sixty-six thousand, eight hundred forty-one".