21654556 has 48 divisors (see below), whose sum is σ = 47642112. Its totient is φ = 8366400.

The previous prime is 21654541. The next prime is 21654559. The reversal of 21654556 is 65545612.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21654559) 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 15 ways as a sum of consecutive naturals, for example, 51226 + ... + 51646.

It is an arithmetic number, because the mean of its divisors is an integer number (992544).

Almost surely, 2^21654556 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 21654556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23821056).

21654556 is an abundant number, since it is smaller than the sum of its proper divisors (25987556).

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

21654556 is a wasteful number, since it uses less digits than its factorization.

21654556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 608 counting only the distinct ones).

The product of its digits is 36000, while the sum is 34.

The square root of 21654556 is about 4653.4456051403. The cubic root of 21654556 is about 278.7296018910.

The spelling of 21654556 in words is "twenty-one million, six hundred fifty-four thousand, five hundred fifty-six".