2506664561 has 16 divisors (see below), whose sum is σ = 2630730960. Its totient is φ = 2385331200.

The previous prime is 2506664543. The next prime is 2506664581. The reversal of 2506664561 is 1654666052.

It can be written as a sum of positive squares in 8 ways, for example, as 34586161 + 2472078400 = 5881^2 + 49720^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2506664561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2506664581) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 680621 + ... + 684293.

It is an arithmetic number, because the mean of its divisors is an integer number (164420685).

Almost surely, 2^2506664561 is an apocalyptic number.

It is an amenable number.

2506664561 is a deficient number, since it is larger than the sum of its proper divisors (124066399).

2506664561 is a wasteful number, since it uses less digits than its factorization.

2506664561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4036.

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 2506664561 is about 50066.6012527313. The cubic root of 2506664561 is about 1358.4137649823.

The spelling of 2506664561 in words is "two billion, five hundred six million, six hundred sixty-four thousand, five hundred sixty-one".