991432620 has 144 divisors (see below), whose sum is σ = 3077343360. Its totient is φ = 258306048.

The previous prime is 991432619. The next prime is 991432627. The reversal of 991432620 is 26234199.

991432620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (991432627) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1606552 + ... + 1607168.

It is an arithmetic number, because the mean of its divisors is an integer number (21370440).

Almost surely, 2^991432620 is an apocalyptic number.

991432620 is a gapful number since it is divisible by the number (90) 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 991432620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1538671680).

991432620 is an abundant number, since it is smaller than the sum of its proper divisors (2085910740).

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

991432620 is a wasteful number, since it uses less digits than its factorization.

991432620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 824 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 991432620 is about 31487.0230412467. The cubic root of 991432620 is about 997.1360120704.

The spelling of 991432620 in words is "nine hundred ninety-one million, four hundred thirty-two thousand, six hundred twenty".