21056454 has 48 divisors (see below), whose sum is σ = 48039264. Its totient is φ = 6652800.

The previous prime is 21056447. The next prime is 21056459. The reversal of 21056454 is 45465012.

21056454 is a `hidden beast` number, since 2 + 10 + 5 + 645 + 4 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056459) 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 23 ways as a sum of consecutive naturals, for example, 74794 + ... + 75074.

It is an arithmetic number, because the mean of its divisors is an integer number (1000818).

Almost surely, 2^21056454 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21056454, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24019632).

21056454 is an abundant number, since it is smaller than the sum of its proper divisors (26982810).

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

21056454 is a wasteful number, since it uses less digits than its factorization.

21056454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 21056454 is about 4588.7311971829. The cubic root of 21056454 is about 276.1394223121.

The spelling of 21056454 in words is "twenty-one million, fifty-six thousand, four hundred fifty-four".