21031300 has 72 divisors (see below), whose sum is σ = 48045536. Its totient is φ = 7983360.

The previous prime is 21031291. The next prime is 21031303. The reversal of 21031300 is 313012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21031303) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 288064 + ... + 288136.

Almost surely, 2^21031300 is an apocalyptic number.

21031300 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 21031300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24022768).

21031300 is an abundant number, since it is smaller than the sum of its proper divisors (27014236).

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

21031300 is a wasteful number, since it uses less digits than its factorization.

21031300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21031300 is about 4585.9895333505. The cubic root of 21031300 is about 276.0294199543.

Adding to 21031300 its reverse (313012), we get a palindrome (21344312).

It can be divided in two parts, 2103 and 1300, that added together give a triangular number (3403 = T₈₂).

The spelling of 21031300 in words is "twenty-one million, thirty-one thousand, three hundred".