991428672 has 112 divisors (see below), whose sum is σ = 2857317120. Its totient is φ = 301559808.

The previous prime is 991428671. The next prime is 991428677. The reversal of 991428672 is 276824199.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (991428671) 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, 219913 + ... + 224375.

It is an arithmetic number, because the mean of its divisors is an integer number (25511760).

Almost surely, 2^991428672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991428672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1428658560).

991428672 is an abundant number, since it is smaller than the sum of its proper divisors (1865888448).

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

991428672 is a wasteful number, since it uses less digits than its factorization.

991428672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4580 (or 4570 counting only the distinct ones).

The product of its digits is 435456, while the sum is 48.

The square root of 991428672 is about 31486.9603486904. The cubic root of 991428672 is about 997.1346884981.

The spelling of 991428672 in words is "nine hundred ninety-one million, four hundred twenty-eight thousand, six hundred seventy-two".