9618991 has 16 divisors (see below), whose sum is σ = 10805184. Its totient is φ = 8515584.

The previous prime is 9618967. The next prime is 9619007. The reversal of 9618991 is 1998169.

9618991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 9618991 - 2¹⁹ = 9094703 is a prime.

It is an Ulam number.

It is a Duffinian number.

9618991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9618941) 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, 28375 + ... + 28711.

It is an arithmetic number, because the mean of its divisors is an integer number (675324).

Almost surely, 2^9618991 is an apocalyptic number.

9618991 is a deficient number, since it is larger than the sum of its proper divisors (1186193).

9618991 is a wasteful number, since it uses less digits than its factorization.

9618991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450.

The product of its digits is 34992, while the sum is 43.

The square root of 9618991 is about 3101.4498222606. The cubic root of 9618991 is about 212.6717670030.

It can be divided in two parts, 9618 and 991, that added together give a square (10609 = 103²).

The spelling of 9618991 in words is "nine million, six hundred eighteen thousand, nine hundred ninety-one".