1991351696 has 20 divisors (see below), whose sum is σ = 4061310000. Its totient is φ = 943271712.

The previous prime is 1991351693. The next prime is 1991351717. The reversal of 1991351696 is 6961531991.

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1991351693) 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, 3274946 + ... + 3275553.

It is an arithmetic number, because the mean of its divisors is an integer number (203065500).

Almost surely, 2^1991351696 is an apocalyptic number.

1991351696 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1991351696 is an abundant number, since it is smaller than the sum of its proper divisors (2069958304).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1991351696 is a wasteful number, since it uses less digits than its factorization.

1991351696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6550526 (or 6550520 counting only the distinct ones).

The product of its digits is 393660, while the sum is 50.

The square root of 1991351696 is about 44624.5638185966. The cubic root of 1991351696 is about 1258.1023959492.

The spelling of 1991351696 in words is "one billion, nine hundred ninety-one million, three hundred fifty-one thousand, six hundred ninety-six".