25521216 has 112 divisors (see below), whose sum is σ = 81783936. Its totient is φ = 6856704.

The previous prime is 25521211. The next prime is 25521227. The reversal of 25521216 is 61212552.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×25521216² = 1302664932237312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (25521211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22290 + ... + 23406.

Almost surely, 2^25521216 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 25521216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40891968).

25521216 is an abundant number, since it is smaller than the sum of its proper divisors (56262720).

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

25521216 is a wasteful number, since it uses less digits than its factorization.

25521216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1156 (or 1146 counting only the distinct ones).

The product of its digits is 1200, while the sum is 24.

The square root of 25521216 is about 5051.8527294449. The cubic root of 25521216 is about 294.4198730284.

Adding to 25521216 its reverse (61212552), we get a palindrome (86733768).

The spelling of 25521216 in words is "twenty-five million, five hundred twenty-one thousand, two hundred sixteen".