21343500 has 240 divisors, whose sum is σ = 76108032. Its totient is φ = 5184000.

The previous prime is 21343489. The next prime is 21343501. The reversal of 21343500 is 534312.

21343500 is nontrivially palindromic in base 7.

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

It is not an unprimeable number, because it can be changed into a prime (21343501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 688485 + ... + 688515.

Almost surely, 2^21343500 is an apocalyptic number.

21343500 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 21343500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38054016).

21343500 is an abundant number, since it is smaller than the sum of its proper divisors (54764532).

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

21343500 is a wasteful number, since it uses less digits than its factorization.

21343500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21343500 is about 4619.9025963758. The cubic root of 21343500 is about 277.3885600744.

Adding to 21343500 its reverse (534312), we get a palindrome (21877812).

The spelling of 21343500 in words is "twenty-one million, three hundred forty-three thousand, five hundred".