2505531561 has 16 divisors (see below), whose sum is σ = 3619238784. Its totient is φ = 1532628864.

The previous prime is 2505531559. The next prime is 2505531563. The reversal of 2505531561 is 1651355052.

It is an interprime number because it is at equal distance from previous prime (2505531559) and next prime (2505531563).

It is not a de Polignac number, because 2505531561 - 2¹ = 2505531559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2505531563) 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, 185836 + ... + 198861.

It is an arithmetic number, because the mean of its divisors is an integer number (226202424).

Almost surely, 2^2505531561 is an apocalyptic number.

It is an amenable number.

2505531561 is a deficient number, since it is larger than the sum of its proper divisors (1113707223).

2505531561 is a wasteful number, since it uses less digits than its factorization.

2505531561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384880.

The product of its (nonzero) digits is 22500, while the sum is 33.

The square root of 2505531561 is about 50055.2850456373. The cubic root of 2505531561 is about 1358.2090687013.

It can be divided in two parts, 25055 and 31561, that added together give a triangular number (56616 = T₃₃₆).

The spelling of 2505531561 in words is "two billion, five hundred five million, five hundred thirty-one thousand, five hundred sixty-one".