1991604713 has 4 divisors (see below), whose sum is σ = 2276119680. Its totient is φ = 1707089748.

The previous prime is 1991604701. The next prime is 1991604731. The reversal of 1991604713 is 3174061991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3174061991 = 33641 ⋅94351.

It is not a de Polignac number, because 1991604713 - 2⁴ = 1991604697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1991604613) 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, 142257473 + ... + 142257486.

It is an arithmetic number, because the mean of its divisors is an integer number (569029920).

Almost surely, 2^1991604713 is an apocalyptic number.

It is an amenable number.

1991604713 is a deficient number, since it is larger than the sum of its proper divisors (284514967).

1991604713 is an equidigital number, since it uses as much as digits as its factorization.

1991604713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284514966.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 1991604713 is about 44627.3986806312. The cubic root of 1991604713 is about 1258.1556776495.

The spelling of 1991604713 in words is "one billion, nine hundred ninety-one million, six hundred four thousand, seven hundred thirteen".