21153456 has 60 divisors (see below), whose sum is σ = 60063120. Its totient is φ = 6948480.

The previous prime is 21153443. The next prime is 21153481. The reversal of 21153456 is 65435112.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9190 + ... + 11258.

It is an arithmetic number, because the mean of its divisors is an integer number (1001052).

Almost surely, 2^21153456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21153456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30031560).

21153456 is an abundant number, since it is smaller than the sum of its proper divisors (38909664).

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

21153456 is a wasteful number, since it uses less digits than its factorization.

21153456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2154 (or 2145 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 21153456 is about 4599.2886406487. The cubic root of 21153456 is about 276.5628087136.

Adding to 21153456 its reverse (65435112), we get a palindrome (86588568).

It can be divided in two parts, 21153 and 456, that added together give a square (21609 = 147²).

The spelling of 21153456 in words is "twenty-one million, one hundred fifty-three thousand, four hundred fifty-six".