21143400 has 96 divisors (see below), whose sum is σ = 66290400. Its totient is φ = 5574400.

The previous prime is 21143383. The next prime is 21143411. The reversal of 21143400 is 434112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21143400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 78466 + ... + 78734.

It is an arithmetic number, because the mean of its divisors is an integer number (690525).

Almost surely, 2^21143400 is an apocalyptic number.

21143400 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 21143400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33145200).

21143400 is an abundant number, since it is smaller than the sum of its proper divisors (45147000).

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

21143400 is a wasteful number, since it uses less digits than its factorization.

21143400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21143400 is about 4598.1952981577. The cubic root of 21143400 is about 276.5189773192.

Adding to 21143400 its reverse (434112), we get a palindrome (21577512).

The spelling of 21143400 in words is "twenty-one million, one hundred forty-three thousand, four hundred".