1391904005 has 4 divisors (see below), whose sum is σ = 1670284812. Its totient is φ = 1113523200.

The previous prime is 1391904001. The next prime is 1391904011. The reversal of 1391904005 is 5004091931.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1005270436 + 386633569 = 31706^2 + 19663^2 .

It is not a de Polignac number, because 1391904005 - 2² = 1391904001 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 (1391904001) 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, 139190396 + ... + 139190405.

It is an arithmetic number, because the mean of its divisors is an integer number (417571203).

Almost surely, 2^1391904005 is an apocalyptic number.

It is an amenable number.

1391904005 is a deficient number, since it is larger than the sum of its proper divisors (278380807).

1391904005 is an equidigital number, since it uses as much as digits as its factorization.

1391904005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278380806.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 1391904005 is about 37308.2297221404. The cubic root of 1391904005 is about 1116.5283671697.

Adding to 1391904005 its reverse (5004091931), we get a palindrome (6395995936).

The spelling of 1391904005 in words is "one billion, three hundred ninety-one million, nine hundred four thousand, five".