25001221440 has 224 divisors, whose sum is σ = 89985006720. Its totient is φ = 5830189056.

The previous prime is 25001221433. The next prime is 25001221451. The reversal of 25001221440 is 4412210052.

It is a super-2 number, since 2×25001221440² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 184402 + ... + 289838.

It is an arithmetic number, because the mean of its divisors is an integer number (401718780).

Almost surely, 2^25001221440 is an apocalyptic number.

25001221440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25001221440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44992503360).

25001221440 is an abundant number, since it is smaller than the sum of its proper divisors (64983785280).

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

25001221440 is a wasteful number, since it uses less digits than its factorization.

25001221440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105489 (or 105479 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

Adding to 25001221440 its reverse (4412210052), we get a palindrome (29413431492).

The spelling of 25001221440 in words is "twenty-five billion, one million, two hundred twenty-one thousand, four hundred forty".