21152502 has 80 divisors (see below), whose sum is σ = 56593152. Its totient is φ = 5773680.

The previous prime is 21152477. The next prime is 21152507. The reversal of 21152502 is 20525112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152507) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 25677 + ... + 26487.

Almost surely, 2^21152502 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21152502, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28296576).

21152502 is an abundant number, since it is smaller than the sum of its proper divisors (35440650).

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

21152502 is a wasteful number, since it uses less digits than its factorization.

21152502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855 (or 846 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21152502 is about 4599.1849277888. The cubic root of 21152502 is about 276.5586510812.

Adding to 21152502 its reverse (20525112), we get a palindrome (41677614).

The spelling of 21152502 in words is "twenty-one million, one hundred fifty-two thousand, five hundred two".