21135006 has 40 divisors (see below), whose sum is σ = 47628504. Its totient is φ = 7004880.

The previous prime is 21135001. The next prime is 21135013. The reversal of 21135006 is 60053112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21135006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135001) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 45616 + ... + 46076.

Almost surely, 2^21135006 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21135006, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23814252).

21135006 is an abundant number, since it is smaller than the sum of its proper divisors (26493498).

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

21135006 is a wasteful number, since it uses less digits than its factorization.

21135006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 758 (or 749 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 21135006 is about 4597.2824581485. The cubic root of 21135006 is about 276.4823794916.

Adding to 21135006 its reverse (60053112), we get a palindrome (81188118).

The spelling of 21135006 in words is "twenty-one million, one hundred thirty-five thousand, six".