25558640 has 20 divisors (see below), whose sum is σ = 59424024. Its totient is φ = 10223424.

The previous prime is 25558619. The next prime is 25558649. The reversal of 25558640 is 4685552.

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 25558640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25558649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159662 + ... + 159821.

Almost surely, 2^25558640 is an apocalyptic number.

25558640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25558640 is an abundant number, since it is smaller than the sum of its proper divisors (33865384).

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

25558640 is a wasteful number, since it uses less digits than its factorization.

25558640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319496 (or 319490 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 35.

The square root of 25558640 is about 5055.5553601954. Note that the first 3 decimals coincide. The cubic root of 25558640 is about 294.5637139798.

The spelling of 25558640 in words is "twenty-five million, five hundred fifty-eight thousand, six hundred forty".