21329400 has 96 divisors (see below), whose sum is σ = 69638400. Its totient is φ = 5385600.

The previous prime is 21329377. The next prime is 21329401. The reversal of 21329400 is 492312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21329401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10465 + ... + 12335.

It is an arithmetic number, because the mean of its divisors is an integer number (725400).

Almost surely, 2^21329400 is an apocalyptic number.

21329400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21329400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34819200).

21329400 is an abundant number, since it is smaller than the sum of its proper divisors (48309000).

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

21329400 is a wasteful number, since it uses less digits than its factorization.

21329400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909 (or 1900 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21329400 is about 4618.3763380651. The cubic root of 21329400 is about 277.3274635613.

The spelling of 21329400 in words is "twenty-one million, three hundred twenty-nine thousand, four hundred".