21453120 has 224 divisors, whose sum is σ = 81930240. Its totient is φ = 5253120.

The previous prime is 21453119. The next prime is 21453143. The reversal of 21453120 is 2135412.

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

It is a junction number, because it is equal to n+sod(n) for n = 21453093 and 21453102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112225 + ... + 112415.

It is an arithmetic number, because the mean of its divisors is an integer number (365760).

Almost surely, 2^21453120 is an apocalyptic number.

21453120 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 21453120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40965120).

21453120 is an abundant number, since it is smaller than the sum of its proper divisors (60477120).

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

21453120 is a wasteful number, since it uses less digits than its factorization.

21453120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 214 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21453120 is about 4631.7512886596. The cubic root of 21453120 is about 277.8626376582.

Adding to 21453120 its reverse (2135412), we get a palindrome (23588532).

The spelling of 21453120 in words is "twenty-one million, four hundred fifty-three thousand, one hundred twenty".