2501565561 has 24 divisors (see below), whose sum is σ = 3947396544. Its totient is φ = 1513971360.

The previous prime is 2501565559. The next prime is 2501565601. The reversal of 2501565561 is 1655651052.

2501565561 is a `hidden beast` number, since 2 + 50 + 1 + 56 + 556 + 1 = 666.

It is not a de Polignac number, because 2501565561 - 2¹ = 2501565559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2501565551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54595 + ... + 89351.

It is an arithmetic number, because the mean of its divisors is an integer number (164474856).

Almost surely, 2^2501565561 is an apocalyptic number.

It is an amenable number.

2501565561 is a deficient number, since it is larger than the sum of its proper divisors (1445830983).

2501565561 is a wasteful number, since it uses less digits than its factorization.

2501565561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35501 (or 35498 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

The square root of 2501565561 is about 50015.6531597859. The cubic root of 2501565561 is about 1357.4920549376.

The spelling of 2501565561 in words is "two billion, five hundred one million, five hundred sixty-five thousand, five hundred sixty-one".