21606036 has 24 divisors (see below), whose sum is σ = 51270240. Its totient is φ = 7079712.

The previous prime is 21606023. The next prime is 21606037. The reversal of 21606036 is 63060612.

It is a junction number, because it is equal to n+sod(n) for n = 21605997 and 21606015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21606037) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14551 + ... + 15966.

It is an arithmetic number, because the mean of its divisors is an integer number (2136260).

Almost surely, 2^21606036 is an apocalyptic number.

It is an amenable number.

21606036 is an abundant number, since it is smaller than the sum of its proper divisors (29664204).

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

21606036 is a wasteful number, since it uses less digits than its factorization.

21606036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30583 (or 30581 counting only the distinct ones).

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

The square root of 21606036 is about 4648.2293402972. The cubic root of 21606036 is about 278.5212689250.

Adding to 21606036 its reverse (63060612), we get a palindrome (84666648).

The spelling of 21606036 in words is "twenty-one million, six hundred six thousand, thirty-six".