25509640 has 32 divisors (see below), whose sum is σ = 61813080. Its totient is φ = 9418752.

The previous prime is 25509629. The next prime is 25509641. The reversal of 25509640 is 4690552.

It can be written as a sum of positive squares in 4 ways, for example, as 19873764 + 5635876 = 4458^2 + 2374^2 .

It is not an unprimeable number, because it can be changed into a prime (25509641) 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 7 ways as a sum of consecutive naturals, for example, 24009 + ... + 25048.

Almost surely, 2^25509640 is an apocalyptic number.

25509640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25509640 is an abundant number, since it is smaller than the sum of its proper divisors (36303440).

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

25509640 is a wasteful number, since it uses less digits than its factorization.

25509640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49081 (or 49077 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 25509640 is about 5050.7068812197. The cubic root of 25509640 is about 294.3753516403.

The spelling of 25509640 in words is "twenty-five million, five hundred nine thousand, six hundred forty".