1991463805 has 8 divisors (see below), whose sum is σ = 2390284512. Its totient is φ = 1592819088.

The previous prime is 1991463781. The next prime is 1991463857. The reversal of 1991463805 is 5083641991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1991463805 - 2¹⁵ = 1991431037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17667 + ... + 65536.

It is an arithmetic number, because the mean of its divisors is an integer number (298785564).

Almost surely, 2^1991463805 is an apocalyptic number.

It is an amenable number.

1991463805 is a deficient number, since it is larger than the sum of its proper divisors (398820707).

1991463805 is an equidigital number, since it uses as much as digits as its factorization.

1991463805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87995.

The product of its (nonzero) digits is 233280, while the sum is 46.

The square root of 1991463805 is about 44625.8199364449. The cubic root of 1991463805 is about 1258.1260050309.

The spelling of 1991463805 in words is "one billion, nine hundred ninety-one million, four hundred sixty-three thousand, eight hundred five".