21054500 has 48 divisors (see below), whose sum is σ = 48707568. Its totient is φ = 7923200.

The previous prime is 21054457. The next prime is 21054521. The reversal of 21054500 is 545012.

It can be written as a sum of positive squares in 8 ways, for example, as 4096576 + 16957924 = 2024^2 + 4118^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7262 + ... + 9738.

It is an arithmetic number, because the mean of its divisors is an integer number (1014741).

Almost surely, 2^21054500 is an apocalyptic number.

21054500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21054500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24353784).

21054500 is an abundant number, since it is smaller than the sum of its proper divisors (27653068).

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

21054500 is a wasteful number, since it uses less digits than its factorization.

21054500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2513 (or 2501 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 21054500 is about 4588.5182793577. The cubic root of 21054500 is about 276.1308803053.

Adding to 21054500 its reverse (545012), we get a palindrome (21599512).

The spelling of 21054500 in words is "twenty-one million, fifty-four thousand, five hundred".