25406640 has 180 divisors, whose sum is σ = 98905872. Its totient is φ = 5725440.

The previous prime is 25406627. The next prime is 25406657. The reversal of 25406640 is 4660452.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (180).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 357805 + ... + 357875.

Almost surely, 2^25406640 is an apocalyptic number.

25406640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is a pronic number, being equal to 5040×5041.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25406640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49452936).

25406640 is an abundant number, since it is smaller than the sum of its proper divisors (73499232).

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

25406640 is a wasteful number, since it uses less digits than its factorization.

25406640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 25406640 is about 5040.4999752009. The cubic root of 25406640 is about 293.9786184645.

It can be divided in two parts, 2540 and 6640, that added together give a triangular number (9180 = T₁₃₅).

The spelling of 25406640 in words is "twenty-five million, four hundred six thousand, six hundred forty".