21075860 has 48 divisors (see below), whose sum is σ = 48187776. Its totient is φ = 7696512.

The previous prime is 21075851. The next prime is 21075863. The reversal of 21075860 is 6857012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21075863) 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 15 ways as a sum of consecutive naturals, for example, 26387 + ... + 27173.

It is an arithmetic number, because the mean of its divisors is an integer number (1003912).

Almost surely, 2^21075860 is an apocalyptic number.

21075860 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 21075860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24093888).

21075860 is an abundant number, since it is smaller than the sum of its proper divisors (27111916).

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

21075860 is a wasteful number, since it uses less digits than its factorization.

21075860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912 (or 910 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 21075860 is about 4590.8452380798. The cubic root of 21075860 is about 276.2242279213.

The spelling of 21075860 in words is "twenty-one million, seventy-five thousand, eight hundred sixty".