2561009321 has 4 divisors (see below), whose sum is σ = 2758010052. Its totient is φ = 2364008592.

The previous prime is 2561009303. The next prime is 2561009323. The reversal of 2561009321 is 1239001652.

2561009321 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 1187491600 + 1373517721 = 34460^2 + 37061^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561009321 - 2²² = 2556815017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561009323) 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, 98500346 + ... + 98500371.

It is an arithmetic number, because the mean of its divisors is an integer number (689502513).

Almost surely, 2^2561009321 is an apocalyptic number.

It is an amenable number.

2561009321 is a deficient number, since it is larger than the sum of its proper divisors (197000731).

2561009321 is a wasteful number, since it uses less digits than its factorization.

2561009321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197000730.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 2561009321 is about 50606.4158086700. The cubic root of 2561009321 is about 1368.1605164933.

The spelling of 2561009321 in words is "two billion, five hundred sixty-one million, nine thousand, three hundred twenty-one".