1391711999 has 4 divisors (see below), whose sum is σ = 1398923136. Its totient is φ = 1384500864.

The previous prime is 1391711963. The next prime is 1391712013. The reversal of 1391711999 is 9991171931.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1391711999 - 2⁸ = 1391711743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1391711939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3605279 + ... + 3605664.

It is an arithmetic number, because the mean of its divisors is an integer number (349730784).

Almost surely, 2^1391711999 is an apocalyptic number.

1391711999 is a deficient number, since it is larger than the sum of its proper divisors (7211137).

1391711999 is an equidigital number, since it uses as much as digits as its factorization.

1391711999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7211136.

The product of its digits is 137781, while the sum is 50.

The square root of 1391711999 is about 37305.6563941716. The cubic root of 1391711999 is about 1116.4770250266.

The spelling of 1391711999 in words is "one billion, three hundred ninety-one million, seven hundred eleven thousand, nine hundred ninety-nine".