25999640 has 16 divisors (see below), whose sum is σ = 58499280. Its totient is φ = 10399840.

The previous prime is 25999639. The next prime is 25999643. The reversal of 25999640 is 4699952.

It is a junction number, because it is equal to n+sod(n) for n = 25999591 and 25999600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25999643) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 324956 + ... + 325035.

It is an arithmetic number, because the mean of its divisors is an integer number (3656205).

Almost surely, 2^25999640 is an apocalyptic number.

25999640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25999640 is an abundant number, since it is smaller than the sum of its proper divisors (32499640).

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

25999640 is a wasteful number, since it uses less digits than its factorization.

25999640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650002 (or 649998 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 44.

The square root of 25999640 is about 5098.9842125663. The cubic root of 25999640 is about 296.2482395285.

It can be divided in two parts, 259 and 99640, that added together give a palindrome (99899).

The spelling of 25999640 in words is "twenty-five million, nine hundred ninety-nine thousand, six hundred forty".