2561969965 has 4 divisors (see below), whose sum is σ = 3074363964. Its totient is φ = 2049575968.

The previous prime is 2561969957. The next prime is 2561969981. The reversal of 2561969965 is 5699691652.

2561969965 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 1619418564 + 942551401 = 40242^2 + 30701^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561969965 - 2³ = 2561969957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256196992 + ... + 256197001.

It is an arithmetic number, because the mean of its divisors is an integer number (768590991).

Almost surely, 2^2561969965 is an apocalyptic number.

It is an amenable number.

2561969965 is a deficient number, since it is larger than the sum of its proper divisors (512393999).

2561969965 is an equidigital number, since it uses as much as digits as its factorization.

2561969965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512393998.

The product of its digits is 7873200, while the sum is 58.

The square root of 2561969965 is about 50615.9062449740. The cubic root of 2561969965 is about 1368.3315624529.

The spelling of 2561969965 in words is "two billion, five hundred sixty-one million, nine hundred sixty-nine thousand, nine hundred sixty-five".