21412420 has 12 divisors (see below), whose sum is σ = 44966124. Its totient is φ = 8564960.

The previous prime is 21412387. The next prime is 21412429. The reversal of 21412420 is 2421412.

It can be written as a sum of positive squares in 2 ways, for example, as 7214596 + 14197824 = 2686^2 + 3768^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21412394 and 21412403.

It is not an unprimeable number, because it can be changed into a prime (21412429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 535291 + ... + 535330.

It is an arithmetic number, because the mean of its divisors is an integer number (3747177).

Almost surely, 2^21412420 is an apocalyptic number.

21412420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21412420 is an abundant number, since it is smaller than the sum of its proper divisors (23553704).

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

21412420 is a wasteful number, since it uses less digits than its factorization.

21412420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070630 (or 1070628 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21412420 is about 4627.3556163321. The cubic root of 21412420 is about 277.6868097978.

Adding to 21412420 its reverse (2421412), we get a palindrome (23833832).

The spelling of 21412420 in words is "twenty-one million, four hundred twelve thousand, four hundred twenty".