1991719752 has 128 divisors (see below), whose sum is σ = 5678069760. Its totient is φ = 576817920.

The previous prime is 1991719729. The next prime is 1991719811. The reversal of 1991719752 is 2579171991.

It is a junction number, because it is equal to n+sod(n) for n = 1991719695 and 1991719704.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 531678 + ... + 535410.

It is an arithmetic number, because the mean of its divisors is an integer number (44359920).

Almost surely, 2^1991719752 is an apocalyptic number.

1991719752 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991719752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2839034880).

1991719752 is an abundant number, since it is smaller than the sum of its proper divisors (3686350008).

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

1991719752 is a wasteful number, since it uses less digits than its factorization.

1991719752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3843 (or 3839 counting only the distinct ones).

The product of its digits is 357210, while the sum is 51.

The square root of 1991719752 is about 44628.6875451206. The cubic root of 1991719752 is about 1258.1799016975.

The spelling of 1991719752 in words is "one billion, nine hundred ninety-one million, seven hundred nineteen thousand, seven hundred fifty-two".