21548540 has 48 divisors (see below), whose sum is σ = 49500192. Its totient is φ = 7831296.

The previous prime is 21548531. The next prime is 21548551. The reversal of 21548540 is 4584512.

It is a super-2 number, since 2×21548540² = 928679152263200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16802 + ... + 18038.

It is an arithmetic number, because the mean of its divisors is an integer number (1031254).

Almost surely, 2^21548540 is an apocalyptic number.

21548540 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 21548540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24750096).

21548540 is an abundant number, since it is smaller than the sum of its proper divisors (27951652).

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

21548540 is a wasteful number, since it uses less digits than its factorization.

21548540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1326 (or 1324 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 29.

The square root of 21548540 is about 4642.0404996079. The cubic root of 21548540 is about 278.2739910380.

The spelling of 21548540 in words is "twenty-one million, five hundred forty-eight thousand, five hundred forty".