25729978 has 4 divisors (see below), whose sum is σ = 38594970. Its totient is φ = 12864988.

The previous prime is 25729927. The next prime is 25729981. The reversal of 25729978 is 87992752.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16867449 + 8862529 = 4107^2 + 2977^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6432493 + ... + 6432496.

Almost surely, 2^25729978 is an apocalyptic number.

25729978 is a deficient number, since it is larger than the sum of its proper divisors (12864992).

25729978 is a wasteful number, since it uses less digits than its factorization.

25729978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12864991.

The product of its digits is 635040, while the sum is 49.

The square root of 25729978 is about 5072.4725726218. The cubic root of 25729978 is about 295.2204729328.

The spelling of 25729978 in words is "twenty-five million, seven hundred twenty-nine thousand, nine hundred seventy-eight".