9900891 has 72 divisors (see below), whose sum is σ = 19669104. Its totient is φ = 4717440.

The previous prime is 9900889. The next prime is 9900893. The reversal of 9900891 is 1980099.

9900891 = 169² + 170² + ... + 325².

It is an interprime number because it is at equal distance from previous prime (9900889) and next prime (9900893).

It is not a de Polignac number, because 9900891 - 2¹ = 9900889 is a prime.

It is an Ulam number.

9900891 is a modest number, since divided by 891 gives 99 as remainder.

It is not an unprimeable number, because it can be changed into a prime (9900893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 62985 + ... + 63141.

It is an arithmetic number, because the mean of its divisors is an integer number (273182).

Almost surely, 2^9900891 is an apocalyptic number.

9900891 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

9900891 is a deficient number, since it is larger than the sum of its proper divisors (9768213).

9900891 is a wasteful number, since it uses less digits than its factorization.

9900891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 9900891 is about 3146.5681305193. The cubic root of 9900891 is about 214.7293583962.

It can be divided in two parts, 99008 and 91, that added together give a palindrome (99099).

The spelling of 9900891 in words is "nine million, nine hundred thousand, eight hundred ninety-one".