21316436 has 12 divisors (see below), whose sum is σ = 39498228. Its totient is φ = 10031232.

The previous prime is 21316417. The next prime is 21316459. The reversal of 21316436 is 63461312.

It can be written as a sum of positive squares in 2 ways, for example, as 18232900 + 3083536 = 4270^2 + 1756^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156671 + ... + 156806.

It is an arithmetic number, because the mean of its divisors is an integer number (3291519).

Almost surely, 2^21316436 is an apocalyptic number.

It is an amenable number.

21316436 is a deficient number, since it is larger than the sum of its proper divisors (18181792).

21316436 is a wasteful number, since it uses less digits than its factorization.

21316436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313498 (or 313496 counting only the distinct ones).

The product of its digits is 2592, while the sum is 26.

The square root of 21316436 is about 4616.9726011749. The cubic root of 21316436 is about 277.2712656703.

Adding to 21316436 its reverse (63461312), we get a palindrome (84777748).

The spelling of 21316436 in words is "twenty-one million, three hundred sixteen thousand, four hundred thirty-six".