21421136 has 20 divisors (see below), whose sum is σ = 45276864. Its totient is φ = 9736800.

The previous prime is 21421133. The next prime is 21421159. The reversal of 21421136 is 63112412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421133) 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, 60680 + ... + 61031.

Almost surely, 2^21421136 is an apocalyptic number.

It is an amenable number.

21421136 is an abundant number, since it is smaller than the sum of its proper divisors (23855728).

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

21421136 is a wasteful number, since it uses less digits than its factorization.

21421136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121730 (or 121724 counting only the distinct ones).

The product of its digits is 288, while the sum is 20.

The square root of 21421136 is about 4628.2973111070. The cubic root of 21421136 is about 277.7244824804.

Adding to 21421136 its reverse (63112412), we get a palindrome (84533548).

The spelling of 21421136 in words is "twenty-one million, four hundred twenty-one thousand, one hundred thirty-six".