25509978 has 40 divisors (see below), whose sum is σ = 61563348. Its totient is φ = 7848576.

The previous prime is 25509971. The next prime is 25509997. The reversal of 25509978 is 87990552.

It is a happy number.

25509978 is a `hidden beast` number, since 2 + 550 + 9 + 97 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 23357889 + 2152089 = 4833^2 + 1467^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25509971) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3951 + ... + 8162.

Almost surely, 2^25509978 is an apocalyptic number.

25509978 is an abundant number, since it is smaller than the sum of its proper divisors (36053370).

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

25509978 is a wasteful number, since it uses less digits than its factorization.

25509978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12140 (or 12131 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The square root of 25509978 is about 5050.7403417717. The cubic root of 25509978 is about 294.3766517819.

The spelling of 25509978 in words is "twenty-five million, five hundred nine thousand, nine hundred seventy-eight".