21113856 has 132 divisors (see below), whose sum is σ = 63866400. Its totient is φ = 6709248.

The previous prime is 21113843. The next prime is 21113861. The reversal of 21113856 is 65831112.

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, 267225 + ... + 267303.

Almost surely, 2^21113856 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 21113856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31933200).

21113856 is an abundant number, since it is smaller than the sum of its proper divisors (42752544).

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

21113856 is a wasteful number, since it uses less digits than its factorization.

21113856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134 (or 113 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 21113856 is about 4594.9816104093. The cubic root of 21113856 is about 276.3901225350.

Adding to 21113856 its reverse (65831112), we get a palindrome (86944968).

The spelling of 21113856 in words is "twenty-one million, one hundred thirteen thousand, eight hundred fifty-six".