2561356745 has 8 divisors (see below), whose sum is σ = 3074003784. Its totient is φ = 2048834944.

The previous prime is 2561356739. The next prime is 2561356801. The reversal of 2561356745 is 5476531652.

It is a happy number.

2561356745 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 645718921 + 1915637824 = 25411^2 + 43768^2 .

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 2561356745 - 2⁴ = 2561356729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2561356696 and 2561356705.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21917 + ... + 74853.

It is an arithmetic number, because the mean of its divisors is an integer number (384250473).

Almost surely, 2^2561356745 is an apocalyptic number.

It is an amenable number.

2561356745 is a deficient number, since it is larger than the sum of its proper divisors (512647039).

2561356745 is an equidigital number, since it uses as much as digits as its factorization.

2561356745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62619.

The product of its digits is 756000, while the sum is 44.

The square root of 2561356745 is about 50609.8483005037. The cubic root of 2561356745 is about 1368.2223814649. Note that the first 3 decimals are identical.

The spelling of 2561356745 in words is "two billion, five hundred sixty-one million, three hundred fifty-six thousand, seven hundred forty-five".