2561232640 has 36 divisors (see below), whose sum is σ = 6134955624. Its totient is φ = 1024492544.

The previous prime is 2561232599. The next prime is 2561232647. The reversal of 2561232640 is 462321652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561232647) 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, 999202 + ... + 1001761.

It is an arithmetic number, because the mean of its divisors is an integer number (170415434).

Almost surely, 2^2561232640 is an apocalyptic number.

2561232640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561232640 is an abundant number, since it is smaller than the sum of its proper divisors (3573722984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2561232640 is an equidigital number, since it uses as much as digits as its factorization.

2561232640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000984 (or 2000970 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 2561232640 is about 50608.6221902948. The cubic root of 2561232640 is about 1368.2002830228.

The spelling of 2561232640 in words is "two billion, five hundred sixty-one million, two hundred thirty-two thousand, six hundred forty".