21636156 has 24 divisors (see below), whose sum is σ = 50560720. Its totient is φ = 7201152.

The previous prime is 21636143. The next prime is 21636161. The reversal of 21636156 is 65163612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12750 + ... + 14346.

Almost surely, 2^21636156 is an apocalyptic number.

It is an amenable number.

21636156 is an abundant number, since it is smaller than the sum of its proper divisors (28924564).

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

21636156 is a wasteful number, since it uses less digits than its factorization.

21636156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2733 (or 2731 counting only the distinct ones).

The product of its digits is 6480, while the sum is 30.

The square root of 21636156 is about 4651.4681553247. The cubic root of 21636156 is about 278.6506334749.

Adding to 21636156 its reverse (65163612), we get a palindrome (86799768).

The spelling of 21636156 in words is "twenty-one million, six hundred thirty-six thousand, one hundred fifty-six".