21403800 has 288 divisors, whose sum is σ = 83566080. Its totient is φ = 4857600.

The previous prime is 21403787. The next prime is 21403801. The reversal of 21403800 is 830412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403801) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 455377 + ... + 455423.

It is an arithmetic number, because the mean of its divisors is an integer number (290160).

Almost surely, 2^21403800 is an apocalyptic number.

21403800 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 21403800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41783040).

21403800 is an abundant number, since it is smaller than the sum of its proper divisors (62162280).

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

21403800 is a wasteful number, since it uses less digits than its factorization.

21403800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21403800 is about 4626.4241050729. The cubic root of 21403800 is about 277.6495419944.

The spelling of 21403800 in words is "twenty-one million, four hundred three thousand, eight hundred".