9991628 has 12 divisors (see below), whose sum is σ = 17958192. Its totient is φ = 4860720.

The previous prime is 9991603. The next prime is 9991649. The reversal of 9991628 is 8261999.

9991628 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33608 + ... + 33903.

It is an arithmetic number, because the mean of its divisors is an integer number (1496516).

Almost surely, 2^9991628 is an apocalyptic number.

It is an amenable number.

9991628 is a deficient number, since it is larger than the sum of its proper divisors (7966564).

9991628 is a wasteful number, since it uses less digits than its factorization.

9991628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67552 (or 67550 counting only the distinct ones).

The product of its digits is 69984, while the sum is 44.

The square root of 9991628 is about 3160.9536535672. The cubic root of 9991628 is about 215.3833291263.

The spelling of 9991628 in words is "nine million, nine hundred ninety-one thousand, six hundred twenty-eight".