265642663621361 has 4 divisors (see below), whose sum is σ = 286076714669172. Its totient is φ = 245208612573552.

The previous prime is 265642663621343. The next prime is 265642663621373. The reversal of 265642663621361 is 163126366246562.

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 95859157611361 + 169783506010000 = 9790769^2 + 13030100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-265642663621361 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 265642663621361.

It is not an unprimeable number, because it can be changed into a prime (265642663621381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10217025523886 + ... + 10217025523911.

It is an arithmetic number, because the mean of its divisors is an integer number (71519178667293).

Almost surely, 2^{265642663621361} is an apocalyptic number.

It is an amenable number.

265642663621361 is a deficient number, since it is larger than the sum of its proper divisors (20434051047811).

265642663621361 is a wasteful number, since it uses less digits than its factorization.

265642663621361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20434051047810.

The product of its digits is 67184640, while the sum is 59.

The spelling of 265642663621361 in words is "two hundred sixty-five trillion, six hundred forty-two billion, six hundred sixty-three million, six hundred twenty-one thousand, three hundred sixty-one".