21542256 has 60 divisors (see below), whose sum is σ = 60659560. Its totient is φ = 7136640.

The previous prime is 21542233. The next prime is 21542263. The reversal of 21542256 is 65224512.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 30030 + ... + 30738.

Almost surely, 2^21542256 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 21542256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30329780).

21542256 is an abundant number, since it is smaller than the sum of its proper divisors (39117304).

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

21542256 is a wasteful number, since it uses less digits than its factorization.

21542256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 934 (or 925 counting only the distinct ones).

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

The square root of 21542256 is about 4641.3635927387. The cubic root of 21542256 is about 278.2469382575.

Adding to 21542256 its reverse (65224512), we get a palindrome (86766768).

The spelling of 21542256 in words is "twenty-one million, five hundred forty-two thousand, two hundred fifty-six".