21004860 has 48 divisors (see below), whose sum is σ = 62276256. Its totient is φ = 5271552.

The previous prime is 21004847. The next prime is 21004883. The reversal of 21004860 is 6840012.

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, 9277 + ... + 11316.

It is an arithmetic number, because the mean of its divisors is an integer number (1297422).

Almost surely, 2^21004860 is an apocalyptic number.

21004860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004860 is an abundant number, since it is smaller than the sum of its proper divisors (41271396).

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

21004860 is a wasteful number, since it uses less digits than its factorization.

21004860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20622 (or 20620 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21004860 is about 4583.1059337528. The cubic root of 21004860 is about 275.9136991258.

Adding to 21004860 its reverse (6840012), we get a palindrome (27844872).

The spelling of 21004860 in words is "twenty-one million, four thousand, eight hundred sixty".