25626640 has 80 divisors (see below), whose sum is σ = 65839536. Its totient is φ = 9216000.

The previous prime is 25626631. The next prime is 25626641. The reversal of 25626640 is 4662652.

It can be written as a sum of positive squares in 8 ways, for example, as 3196944 + 22429696 = 1788^2 + 4736^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (25626641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42340 + ... + 42940.

Almost surely, 2^25626640 is an apocalyptic number.

25626640 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 25626640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32919768).

25626640 is an abundant number, since it is smaller than the sum of its proper divisors (40212896).

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

25626640 is a wasteful number, since it uses less digits than its factorization.

25626640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668 (or 662 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 25626640 is about 5062.2761678913. The cubic root of 25626640 is about 294.8247163241.

It can be divided in two parts, 256 and 26640, that added together give a square (26896 = 164²).

The spelling of 25626640 in words is "twenty-five million, six hundred twenty-six thousand, six hundred forty".