25643520 has 320 divisors, whose sum is σ = 106064640. Its totient is φ = 5750784.

The previous prime is 25643507. The next prime is 25643533. The reversal of 25643520 is 2534652.

It is an interprime number because it is at equal distance from previous prime (25643507) and next prime (25643533).

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 483814 + ... + 483866.

It is an arithmetic number, because the mean of its divisors is an integer number (331452).

Almost surely, 2^25643520 is an apocalyptic number.

25643520 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 25643520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53032320).

25643520 is an abundant number, since it is smaller than the sum of its proper divisors (80421120).

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

25643520 is an equidigital number, since it uses as much as digits as its factorization.

25643520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

The square root of 25643520 is about 5063.9431276427. The cubic root of 25643520 is about 294.8894347698.

It can be divided in two parts, 2564 and 3520, that added together give a square (6084 = 78²).

The spelling of 25643520 in words is "twenty-five million, six hundred forty-three thousand, five hundred twenty".