21140436 has 12 divisors (see below), whose sum is σ = 49327712. Its totient is φ = 7046808.

The previous prime is 21140423. The next prime is 21140501. The reversal of 21140436 is 63404112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

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, 880840 + ... + 880863.

Almost surely, 2^21140436 is an apocalyptic number.

It is an amenable number.

21140436 is an abundant number, since it is smaller than the sum of its proper divisors (28187276).

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

21140436 is a wasteful number, since it uses less digits than its factorization.

21140436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1761710 (or 1761708 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21140436 is about 4597.8729865015. The cubic root of 21140436 is about 276.5060553901.

Adding to 21140436 its reverse (63404112), we get a palindrome (84544548).

The spelling of 21140436 in words is "twenty-one million, one hundred forty thousand, four hundred thirty-six".