21421416 has 16 divisors (see below), whose sum is σ = 53553600. Its totient is φ = 7140464.

The previous prime is 21421399. The next prime is 21421427. The reversal of 21421416 is 61412412.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21421392 and 21421401.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 446256 + ... + 446303.

It is an arithmetic number, because the mean of its divisors is an integer number (3347100).

Almost surely, 2^21421416 is an apocalyptic number.

It is an amenable number.

21421416 is an abundant number, since it is smaller than the sum of its proper divisors (32132184).

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

21421416 is a wasteful number, since it uses less digits than its factorization.

21421416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892568 (or 892564 counting only the distinct ones).

The product of its digits is 384, while the sum is 21.

The square root of 21421416 is about 4628.3275597131. The cubic root of 21421416 is about 277.7256925395.

Adding to 21421416 its reverse (61412412), we get a palindrome (82833828).

The spelling of 21421416 in words is "twenty-one million, four hundred twenty-one thousand, four hundred sixteen".