21421356 has 36 divisors (see below), whose sum is σ = 54943896. Its totient is φ = 6490880.

The previous prime is 21421333. The next prime is 21421373. The reversal of 21421356 is 65312412.

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 11 ways as a sum of consecutive naturals, for example, 5925 + ... + 8828.

Almost surely, 2^21421356 is an apocalyptic number.

It is an amenable number.

21421356 is an abundant number, since it is smaller than the sum of its proper divisors (33522540).

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

21421356 is a wasteful number, since it uses less digits than its factorization.

21421356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14782 (or 14769 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 21421356 is about 4628.3210778856. The cubic root of 21421356 is about 277.7254332420.

Adding to 21421356 its reverse (65312412), we get a palindrome (86733768).

The spelling of 21421356 in words is "twenty-one million, four hundred twenty-one thousand, three hundred fifty-six".