21362420 has 24 divisors (see below), whose sum is σ = 44950248. Its totient is φ = 8528000.

The previous prime is 21362417. The next prime is 21362447. The reversal of 21362420 is 2426312.

21362420 = 361² + 362² + ... + 480².

It can be written as a sum of positive squares in 4 ways, for example, as 605284 + 20757136 = 778^2 + 4556^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21362392 and 21362401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15770 + ... + 17070.

It is an arithmetic number, because the mean of its divisors is an integer number (1872927).

Almost surely, 2^21362420 is an apocalyptic number.

21362420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21362420 is an abundant number, since it is smaller than the sum of its proper divisors (23587828).

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

21362420 is a wasteful number, since it uses less digits than its factorization.

21362420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2131 (or 2129 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21362420 is about 4621.9498050065. The cubic root of 21362420 is about 277.4704997994.

Adding to 21362420 its reverse (2426312), we get a palindrome (23788732).

The spelling of 21362420 in words is "twenty-one million, three hundred sixty-two thousand, four hundred twenty".