25221816 has 96 divisors (see below), whose sum is σ = 73008000. Its totient is φ = 7843392.

The previous prime is 25221787. The next prime is 25221839. The reversal of 25221816 is 61812252.

It is a happy number.

It is a super-2 number, since 2×25221816² = 1272280004675712, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 25221816.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 140815 + ... + 140993.

It is an arithmetic number, because the mean of its divisors is an integer number (760500).

Almost surely, 2^25221816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25221816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36504000).

25221816 is an abundant number, since it is smaller than the sum of its proper divisors (47786184).

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

25221816 is a wasteful number, since it uses less digits than its factorization.

25221816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313 (or 306 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 25221816 is about 5022.1326147365. The cubic root of 25221816 is about 293.2640205837.

It can be divided in two parts, 25 and 221816, that added together give a square (221841 = 471²).

The spelling of 25221816 in words is "twenty-five million, two hundred twenty-one thousand, eight hundred sixteen".