21316356 has 18 divisors (see below), whose sum is σ = 53883102. Its totient is φ = 7105440.

The previous prime is 21316349. The next prime is 21316369. The reversal of 21316356 is 65361312.

21316356 is a `hidden beast` number, since 21 + 3 + 1 + 635 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19713600 + 1602756 = 4440^2 + 1266^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 296025 + ... + 296096.

Almost surely, 2^21316356 is an apocalyptic number.

It is an amenable number.

21316356 is an abundant number, since it is smaller than the sum of its proper divisors (32566746).

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

21316356 is a wasteful number, since it uses less digits than its factorization.

21316356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592131 (or 592126 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 21316356 is about 4616.9639374810. The cubic root of 21316356 is about 277.2709188061.

Adding to 21316356 its reverse (65361312), we get a palindrome (86677668).

The spelling of 21316356 in words is "twenty-one million, three hundred sixteen thousand, three hundred fifty-six".