21200120 has 32 divisors (see below), whose sum is σ = 47833200. Its totient is φ = 8456448.

The previous prime is 21200117. The next prime is 21200129. The reversal of 21200120 is 2100212.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a junction number, because it is equal to n+sod(n) for n = 21200098 and 21200107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24251 + ... + 25109.

Almost surely, 2^21200120 is an apocalyptic number.

21200120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200120 is an abundant number, since it is smaller than the sum of its proper divisors (26633080).

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

21200120 is a wasteful number, since it uses less digits than its factorization.

21200120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1487 (or 1483 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21200120 is about 4604.3588044374. The cubic root of 21200120 is about 276.7660229270.

Adding to 21200120 its reverse (2100212), we get a palindrome (23300332).

The spelling of 21200120 in words is "twenty-one million, two hundred thousand, one hundred twenty".