25649840 has 40 divisors (see below), whose sum is σ = 59848848. Its totient is φ = 10223360.

The previous prime is 25649839. The next prime is 25649849. The reversal of 25649840 is 4894652.

25649840 = T₄₅ + T₄₆ + ... + T₅₃₅.

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 = 25649794 and 25649803.

It is not an unprimeable number, because it can be changed into a prime (25649849) 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, 38954 + ... + 39606.

Almost surely, 2^25649840 is an apocalyptic number.

25649840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25649840 is an abundant number, since it is smaller than the sum of its proper divisors (34199008).

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

25649840 is a wasteful number, since it uses less digits than its factorization.

25649840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1157 (or 1151 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 25649840 is about 5064.5671088455. The cubic root of 25649840 is about 294.9136585391.

The spelling of 25649840 in words is "twenty-five million, six hundred forty-nine thousand, eight hundred forty".