21220200 has 72 divisors (see below), whose sum is σ = 71270550. Its totient is φ = 5658240.

The previous prime is 21220159. The next prime is 21220211. The reversal of 21220200 is 202212.

It can be written as a sum of positive squares in 3 ways, for example, as 9400356 + 11819844 = 3066^2 + 3438^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4095 + ... + 7694.

Almost surely, 2^21220200 is an apocalyptic number.

21220200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220200 is an abundant number, since it is smaller than the sum of its proper divisors (50050350).

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

21220200 is a wasteful number, since it uses less digits than its factorization.

21220200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11811 (or 11799 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 21220200 is about 4606.5388308360. The cubic root of 21220200 is about 276.8533763327.

Adding to 21220200 its reverse (202212), we get a palindrome (21422412).

The spelling of 21220200 in words is "twenty-one million, two hundred twenty thousand, two hundred".