9991020 has 48 divisors (see below), whose sum is σ = 30129120. Its totient is φ = 2459136.

The previous prime is 9990997. The next prime is 9991027. The reversal of 9991020 is 201999.

9991020 is digitally balanced in base 2 and base 4, because in such bases 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 (30).

It is not an unprimeable number, because it can be changed into a prime (9991027) 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, 5625 + ... + 7184.

It is an arithmetic number, because the mean of its divisors is an integer number (627690).

Almost surely, 2^9991020 is an apocalyptic number.

It is an amenable number.

9991020 is an abundant number, since it is smaller than the sum of its proper divisors (20138100).

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

9991020 is a wasteful number, since it uses less digits than its factorization.

9991020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12834 (or 12832 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 30.

The square root of 9991020 is about 3160.8574785966. The cubic root of 9991020 is about 215.3789602780.

It can be divided in two parts, 99 and 91020, that added together give a palindrome (91119).

The spelling of 9991020 in words is "nine million, nine hundred ninety-one thousand, twenty".