21530580 has 48 divisors (see below), whose sum is σ = 60587520. Its totient is φ = 5712768.

The previous prime is 21530569. The next prime is 21530609. The reversal of 21530580 is 8503512.

It is a super-3 number, since 3×21530580³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21530580.

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 15 ways as a sum of consecutive naturals, for example, 12957 + ... + 14523.

It is an arithmetic number, because the mean of its divisors is an integer number (1262240).

Almost surely, 2^21530580 is an apocalyptic number.

21530580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21530580 is an abundant number, since it is smaller than the sum of its proper divisors (39056940).

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

21530580 is a wasteful number, since it uses less digits than its factorization.

21530580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1808 (or 1806 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21530580 is about 4640.1056022466. The cubic root of 21530580 is about 278.1966588069.

The spelling of 21530580 in words is "twenty-one million, five hundred thirty thousand, five hundred eighty".