2561556604 has 6 divisors (see below), whose sum is σ = 4482724064. Its totient is φ = 1280778300.

The previous prime is 2561556589. The next prime is 2561556607. The reversal of 2561556604 is 4066551652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561556607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320194572 + ... + 320194579.

Almost surely, 2^2561556604 is an apocalyptic number.

It is an amenable number.

2561556604 is a deficient number, since it is larger than the sum of its proper divisors (1921167460).

2561556604 is a wasteful number, since it uses less digits than its factorization.

2561556604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640389155 (or 640389153 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 40.

The square root of 2561556604 is about 50611.8227689934. The cubic root of 2561556604 is about 1368.2579673506.

The spelling of 2561556604 in words is "two billion, five hundred sixty-one million, five hundred fifty-six thousand, six hundred four".