21306054 has 64 divisors (see below), whose sum is σ = 53747712. Its totient is φ = 5469600.

The previous prime is 21306023. The next prime is 21306079. The reversal of 21306054 is 45060312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21306054.

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 31 ways as a sum of consecutive naturals, for example, 49219 + ... + 49649.

It is an arithmetic number, because the mean of its divisors is an integer number (839808).

Almost surely, 2^21306054 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21306054, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26873856).

21306054 is an abundant number, since it is smaller than the sum of its proper divisors (32441658).

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

21306054 is a wasteful number, since it uses less digits than its factorization.

21306054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21306054 is about 4615.8481344169. The cubic root of 21306054 is about 277.2262441082.

Adding to 21306054 its reverse (45060312), we get a palindrome (66366366).

The spelling of 21306054 in words is "twenty-one million, three hundred six thousand, fifty-four".