21543480 has 192 divisors, whose sum is σ = 81768960. Its totient is φ = 4817664.

The previous prime is 21543461. The next prime is 21543499. The reversal of 21543480 is 8434512.

It is an interprime number because it is at equal distance from previous prime (21543461) and next prime (21543499).

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 47 ways as a sum of consecutive naturals, for example, 209109 + ... + 209211.

It is an arithmetic number, because the mean of its divisors is an integer number (425880).

Almost surely, 2^21543480 is an apocalyptic number.

21543480 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 21543480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40884480).

21543480 is an abundant number, since it is smaller than the sum of its proper divisors (60225480).

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

21543480 is a wasteful number, since it uses less digits than its factorization.

21543480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 21543480 is about 4641.4954486674. The cubic root of 21543480 is about 278.2522080213.

Adding to 21543480 its reverse (8434512), we get a palindrome (29977992).

The spelling of 21543480 in words is "twenty-one million, five hundred forty-three thousand, four hundred eighty".