21236361 has 16 divisors (see below), whose sum is σ = 28902720. Its totient is φ = 13867200.

The previous prime is 21236359. The next prime is 21236363. The reversal of 21236361 is 16363212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21236359) and next prime (21236363).

It is not a de Polignac number, because 21236361 - 2¹ = 21236359 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21236363) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32706 + ... + 33348.

It is an arithmetic number, because the mean of its divisors is an integer number (1806420).

Almost surely, 2^21236361 is an apocalyptic number.

It is an amenable number.

21236361 is a deficient number, since it is larger than the sum of its proper divisors (7666359).

21236361 is a wasteful number, since it uses less digits than its factorization.

21236361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856.

The product of its digits is 1296, while the sum is 24.

The square root of 21236361 is about 4608.2926339372. The cubic root of 21236361 is about 276.9236410186.

Adding to 21236361 its reverse (16363212), we get a palindrome (37599573).

The spelling of 21236361 in words is "twenty-one million, two hundred thirty-six thousand, three hundred sixty-one".