21210800 has 60 divisors (see below), whose sum is σ = 54892320. Its totient is φ = 7829760.

The previous prime is 21210799. The next prime is 21210823. The reversal of 21210800 is 801212.

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 11 ways as a sum of consecutive naturals, for example, 3161 + ... + 7239.

It is an arithmetic number, because the mean of its divisors is an integer number (914872).

Almost surely, 2^21210800 is an apocalyptic number.

21210800 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 21210800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27446160).

21210800 is an abundant number, since it is smaller than the sum of its proper divisors (33681520).

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

21210800 is a wasteful number, since it uses less digits than its factorization.

21210800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4110 (or 4099 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 21210800 is about 4605.5184290153. The cubic root of 21210800 is about 276.8124906656.

It can be divided in two parts, 21 and 210800, that multiplied together give a triangular number (4426800 = T₂₉₇₅).

The spelling of 21210800 in words is "twenty-one million, two hundred ten thousand, eight hundred".