9921400 has 48 divisors (see below), whose sum is σ = 23324400. Its totient is φ = 3924480.

The previous prime is 9921391. The next prime is 9921407. The reversal of 9921400 is 41299.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9921407) 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 11 ways as a sum of consecutive naturals, for example, 22381 + ... + 22819.

It is an arithmetic number, because the mean of its divisors is an integer number (485925).

Almost surely, 2^9921400 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 9921400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11662200).

9921400 is an abundant number, since it is smaller than the sum of its proper divisors (13403000).

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

9921400 is a wasteful number, since it uses less digits than its factorization.

9921400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568 (or 559 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 9921400 is about 3149.8253919860. The cubic root of 9921400 is about 214.8775217324.

Adding to 9921400 its reverse (41299), we get a palindrome (9962699).

The spelling of 9921400 in words is "nine million, nine hundred twenty-one thousand, four hundred".