21420422 has 16 divisors (see below), whose sum is σ = 32901120. Its totient is φ = 10456008.

The previous prime is 21420403. The next prime is 21420433. The reversal of 21420422 is 22402412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21420422.

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, 19163 + ... + 20249.

It is an arithmetic number, because the mean of its divisors is an integer number (2056320).

Almost surely, 2^21420422 is an apocalyptic number.

21420422 is a deficient number, since it is larger than the sum of its proper divisors (11480698).

21420422 is a wasteful number, since it uses less digits than its factorization.

21420422 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21420422 is about 4628.2201762665. The cubic root of 21420422 is about 277.7213967822.

Adding to 21420422 its reverse (22402412), we get a palindrome (43822834).

The spelling of 21420422 in words is "twenty-one million, four hundred twenty thousand, four hundred twenty-two".