25542640 has 40 divisors (see below), whose sum is σ = 59839920. Its totient is φ = 10139136.

The previous prime is 25542613. The next prime is 25542641. The reversal of 25542640 is 4624552.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 25542599 and 25542608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25542641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9972 + ... + 12268.

It is an arithmetic number, because the mean of its divisors is an integer number (1495998).

Almost surely, 2^25542640 is an apocalyptic number.

25542640 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 25542640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29919960).

25542640 is an abundant number, since it is smaller than the sum of its proper divisors (34297280).

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

25542640 is a wasteful number, since it uses less digits than its factorization.

25542640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2449 (or 2443 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 28.

The square root of 25542640 is about 5053.9726948214. The cubic root of 25542640 is about 294.5022344014.

The spelling of 25542640 in words is "twenty-five million, five hundred forty-two thousand, six hundred forty".