21500252 has 24 divisors (see below), whose sum is σ = 39471600. Its totient is φ = 10233216.

The previous prime is 21500251. The next prime is 21500261. The reversal of 21500252 is 25200512.

It is a self number, because there is not a number n which added to its sum of digits gives 21500252.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500251) 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, 7199 + ... + 9737.

It is an arithmetic number, because the mean of its divisors is an integer number (1644650).

Almost surely, 2^21500252 is an apocalyptic number.

It is an amenable number.

21500252 is a deficient number, since it is larger than the sum of its proper divisors (17971348).

21500252 is a wasteful number, since it uses less digits than its factorization.

21500252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2645 (or 2643 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 21500252 is about 4636.8364215271. The cubic root of 21500252 is about 278.0659747149.

Adding to 21500252 its reverse (25200512), we get a palindrome (46700764).

The spelling of 21500252 in words is "twenty-one million, five hundred thousand, two hundred fifty-two".