21453000 has 64 divisors (see below), whose sum is σ = 66942720. Its totient is φ = 5720000.

The previous prime is 21452999. The next prime is 21453017. The reversal of 21453000 is 35412.

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

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 576 + ... + 6575.

It is an arithmetic number, because the mean of its divisors is an integer number (1045980).

Almost surely, 2^21453000 is an apocalyptic number.

21453000 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 21453000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33471360).

21453000 is an abundant number, since it is smaller than the sum of its proper divisors (45489720).

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

21453000 is a wasteful number, since it uses less digits than its factorization.

21453000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7175 (or 7161 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21453000 is about 4631.7383345781. The cubic root of 21453000 is about 277.8621195739.

Adding to 21453000 its reverse (35412), we get a palindrome (21488412).

The spelling of 21453000 in words is "twenty-one million, four hundred fifty-three thousand".