21200420 has 12 divisors (see below), whose sum is σ = 44520924. Its totient is φ = 8480160.

The previous prime is 21200401. The next prime is 21200461. The reversal of 21200420 is 2400212.

It can be written as a sum of positive squares in 2 ways, for example, as 3290596 + 17909824 = 1814^2 + 4232^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 529991 + ... + 530030.

It is an arithmetic number, because the mean of its divisors is an integer number (3710077).

Almost surely, 2^21200420 is an apocalyptic number.

21200420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200420 is an abundant number, since it is smaller than the sum of its proper divisors (23320504).

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

21200420 is a wasteful number, since it uses less digits than its factorization.

21200420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060030 (or 1060028 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 21200420 is about 4604.3913821481. The cubic root of 21200420 is about 276.7673284135.

Adding to 21200420 its reverse (2400212), we get a palindrome (23600632).

The spelling of 21200420 in words is "twenty-one million, two hundred thousand, four hundred twenty".