2561351636 has 12 divisors (see below), whose sum is σ = 4505591412. Its totient is φ = 1274039808.

The previous prime is 2561351627. The next prime is 2561351641. The reversal of 2561351636 is 6361531652.

It can be written as a sum of positive squares in 2 ways, for example, as 593896900 + 1967454736 = 24370^2 + 44356^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 2561351636.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1658135 + ... + 1659678.

It is an arithmetic number, because the mean of its divisors is an integer number (375465951).

Almost surely, 2^2561351636 is an apocalyptic number.

It is an amenable number.

2561351636 is a deficient number, since it is larger than the sum of its proper divisors (1944239776).

2561351636 is a wasteful number, since it uses less digits than its factorization.

2561351636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3318010 (or 3318008 counting only the distinct ones).

The product of its digits is 97200, while the sum is 38.

The square root of 2561351636 is about 50609.7978261127. The cubic root of 2561351636 is about 1368.2214717579.

The spelling of 2561351636 in words is "two billion, five hundred sixty-one million, three hundred fifty-one thousand, six hundred thirty-six".