21636337 has 4 divisors (see below), whose sum is σ = 21779776. Its totient is φ = 21492900.

The previous prime is 21636331. The next prime is 21636341. The reversal of 21636337 is 73363612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21636337 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21636299 and 21636308.

It is not an unprimeable number, because it can be changed into a prime (21636331) 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, 71493 + ... + 71794.

It is an arithmetic number, because the mean of its divisors is an integer number (5444944).

Almost surely, 2^21636337 is an apocalyptic number.

It is an amenable number.

21636337 is a deficient number, since it is larger than the sum of its proper divisors (143439).

21636337 is a wasteful number, since it uses less digits than its factorization.

21636337 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143438.

The product of its digits is 13608, while the sum is 31.

The square root of 21636337 is about 4651.4876115067. The cubic root of 21636337 is about 278.6514105018.

Adding to 21636337 its reverse (73363612), we get a palindrome (94999949).

The spelling of 21636337 in words is "twenty-one million, six hundred thirty-six thousand, three hundred thirty-seven".