1991428032 has 112 divisors (see below), whose sum is σ = 5760866304. Its totient is φ = 602112000.

The previous prime is 1991428007. The next prime is 1991428037. The reversal of 1991428032 is 2308241991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991428037) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1353057 + ... + 1354527.

Almost surely, 2^1991428032 is an apocalyptic number.

1991428032 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 1991428032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2880433152).

1991428032 is an abundant number, since it is smaller than the sum of its proper divisors (3769438272).

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

1991428032 is a wasteful number, since it uses less digits than its factorization.

1991428032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138 (or 2128 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 1991428032 is about 44625.4191240822. The cubic root of 1991428032 is about 1258.1184716760.

The spelling of 1991428032 in words is "one billion, nine hundred ninety-one million, four hundred twenty-eight thousand, thirty-two".