21080860 has 12 divisors (see below), whose sum is σ = 44269848. Its totient is φ = 8432336.

The previous prime is 21080849. The next prime is 21080869. The reversal of 21080860 is 6808012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21080869) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 527002 + ... + 527041.

It is an arithmetic number, because the mean of its divisors is an integer number (3689154).

Almost surely, 2^21080860 is an apocalyptic number.

21080860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21080860 is an abundant number, since it is smaller than the sum of its proper divisors (23188988).

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

21080860 is a wasteful number, since it uses less digits than its factorization.

21080860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054052 (or 1054050 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 21080860 is about 4591.3897678154. The cubic root of 21080860 is about 276.2460698444.

Adding to 21080860 its reverse (6808012), we get a palindrome (27888872).

The spelling of 21080860 in words is "twenty-one million, eighty thousand, eight hundred sixty".