21572250 has 96 divisors (see below), whose sum is σ = 62741952. Its totient is φ = 4922400.

The previous prime is 21572237. The next prime is 21572251. The reversal of 21572250 is 5227512.

It is a self number, because there is not a number n which added to its sum of digits gives 21572250.

It is not an unprimeable number, because it can be changed into a prime (21572251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36457 + ... + 37043.

It is an arithmetic number, because the mean of its divisors is an integer number (653562).

Almost surely, 2^21572250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21572250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31370976).

21572250 is an abundant number, since it is smaller than the sum of its proper divisors (41169702).

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

21572250 is a wasteful number, since it uses less digits than its factorization.

21572250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621 (or 604 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 21572250 is about 4644.5936313094. The cubic root of 21572250 is about 278.3760158606.

Adding to 21572250 its reverse (5227512), we get a palindrome (26799762).

The spelling of 21572250 in words is "twenty-one million, five hundred seventy-two thousand, two hundred fifty".