2565648381 has 32 divisors (see below), whose sum is σ = 3757142016. Its totient is φ = 1550304000.

The previous prime is 2565648329. The next prime is 2565648383. The reversal of 2565648381 is 1838465652.

It is a happy number.

It is not a de Polignac number, because 2565648381 - 2⁶ = 2565648317 is a prime.

It is a super-2 number, since 2×2565648381² = 13165103229855842322, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2565648381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2565648383) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 329746 + ... + 337436.

It is an arithmetic number, because the mean of its divisors is an integer number (117410688).

Almost surely, 2^2565648381 is an apocalyptic number.

It is an amenable number.

2565648381 is a deficient number, since it is larger than the sum of its proper divisors (1191493635).

2565648381 is a wasteful number, since it uses less digits than its factorization.

2565648381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7953.

The product of its digits is 1382400, while the sum is 48.

The square root of 2565648381 is about 50652.2297732291. The cubic root of 2565648381 is about 1368.9861220050.

The spelling of 2565648381 in words is "two billion, five hundred sixty-five million, six hundred forty-eight thousand, three hundred eighty-one".