25661665 has 8 divisors (see below), whose sum is σ = 31856040. Its totient is φ = 19821312.

The previous prime is 25661659. The next prime is 25661677. The reversal of 25661665 is 56616652.

It can be written as a sum of positive squares in 4 ways, for example, as 891136 + 24770529 = 944^2 + 4977^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25661665 - 2¹³ = 25653473 is a prime.

It is an unprimeable number.

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, 88344 + ... + 88633.

It is an arithmetic number, because the mean of its divisors is an integer number (3982005).

Almost surely, 2^25661665 is an apocalyptic number.

It is an amenable number.

25661665 is a deficient number, since it is larger than the sum of its proper divisors (6194375).

25661665 is a wasteful number, since it uses less digits than its factorization.

25661665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177011.

The product of its digits is 64800, while the sum is 37.

The square root of 25661665 is about 5065.7343988804. The cubic root of 25661665 is about 294.9589715994.

The spelling of 25661665 in words is "twenty-five million, six hundred sixty-one thousand, six hundred sixty-five".