2561902909 has 4 divisors (see below), whose sum is σ = 2673290016. Its totient is φ = 2450515804.

The previous prime is 2561902883. The next prime is 2561902927. The reversal of 2561902909 is 9092091652.

It is a happy number.

2561902909 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2561902909 - 2⁷ = 2561902781 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 (2561902939) 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, 55693519 + ... + 55693564.

It is an arithmetic number, because the mean of its divisors is an integer number (668322504).

Almost surely, 2^2561902909 is an apocalyptic number.

It is an amenable number.

2561902909 is a deficient number, since it is larger than the sum of its proper divisors (111387107).

2561902909 is a wasteful number, since it uses less digits than its factorization.

2561902909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111387106.

The product of its (nonzero) digits is 87480, while the sum is 43.

The square root of 2561902909 is about 50615.2438401713. The cubic root of 2561902909 is about 1368.3196242904.

The spelling of 2561902909 in words is "two billion, five hundred sixty-one million, nine hundred two thousand, nine hundred nine".