25656677667221 has 4 divisors (see below), whose sum is σ = 25705922730444. Its totient is φ = 25607432604000.

The previous prime is 25656677667161. The next prime is 25656677667227. The reversal of 25656677667221 is 12276677665652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16825468756996 + 8831208910225 = 4101886^2 + 2971735^2 .

It is a cyclic number.

It is not a de Polignac number, because 25656677667221 - 2¹⁰ = 25656677666197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25656677667227) 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, 24622530830 + ... + 24622531871.

It is an arithmetic number, because the mean of its divisors is an integer number (6426480682611).

Almost surely, 2^{25656677667221} is an apocalyptic number.

It is an amenable number.

25656677667221 is a deficient number, since it is larger than the sum of its proper divisors (49245063223).

25656677667221 is an equidigital number, since it uses as much as digits as its factorization.

25656677667221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49245063222.

The product of its digits is 533433600, while the sum is 68.

The spelling of 25656677667221 in words is "twenty-five trillion, six hundred fifty-six billion, six hundred seventy-seven million, six hundred sixty-seven thousand, two hundred twenty-one".