2561246545 has 48 divisors (see below), whose sum is σ = 3682744704. Its totient is φ = 1694784000.

The previous prime is 2561246543. The next prime is 2561246557. The reversal of 2561246545 is 5456421652.

2561246545 = 418² + 419² + ... + 1979².

It is a happy number.

It is not a de Polignac number, because 2561246545 - 2¹ = 2561246543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2561246498 and 2561246507.

It is not an unprimeable number, because it can be changed into a prime (2561246543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 658005 + ... + 661885.

It is an arithmetic number, because the mean of its divisors is an integer number (76723848).

Almost surely, 2^2561246545 is an apocalyptic number.

It is an amenable number.

2561246545 is a deficient number, since it is larger than the sum of its proper divisors (1121498159).

2561246545 is a wasteful number, since it uses less digits than its factorization.

2561246545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3994 (or 3981 counting only the distinct ones).

The product of its digits is 288000, while the sum is 40.

The square root of 2561246545 is about 50608.7595678851. The cubic root of 2561246545 is about 1368.2027590169.

The spelling of 2561246545 in words is "two billion, five hundred sixty-one million, two hundred forty-six thousand, five hundred forty-five".