25578666 has 24 divisors (see below), whose sum is σ = 57474144. Its totient is φ = 8526060.

The previous prime is 25578661. The next prime is 25578719. The reversal of 25578666 is 66687552.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25578661) 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 11 ways as a sum of consecutive naturals, for example, 25830 + ... + 26801.

It is an arithmetic number, because the mean of its divisors is an integer number (2394756).

Almost surely, 2^25578666 is an apocalyptic number.

25578666 is an abundant number, since it is smaller than the sum of its proper divisors (31895478).

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

25578666 is an equidigital number, since it uses as much as digits as its factorization.

25578666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52648 (or 52636 counting only the distinct ones).

The product of its digits is 604800, while the sum is 45.

The square root of 25578666 is about 5057.5355658660. The cubic root of 25578666 is about 294.6406272133.

Adding to 25578666 its product of digits (604800), we get a triangular number (26183466 = T₇₂₃₆).

It can be divided in two parts, 25578 and 666, that added together give a square (26244 = 162²).

The spelling of 25578666 in words is "twenty-five million, five hundred seventy-eight thousand, six hundred sixty-six".