2561261044 has 18 divisors (see below), whose sum is σ = 4631465202. Its totient is φ = 1239318000.

The previous prime is 2561261039. The next prime is 2561261069. The reversal of 2561261044 is 4401621652.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 2522048400 + 39212644 = 50220^2 + 6262^2 .

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 2561260997 and 2561261015.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 329307 + ... + 336994.

Almost surely, 2^2561261044 is an apocalyptic number.

It is an amenable number.

2561261044 is a deficient number, since it is larger than the sum of its proper divisors (2070204158).

2561261044 is a wasteful number, since it uses less digits than its factorization.

2561261044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666367 (or 666334 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 2561261044 is about 50608.9028136355. The cubic root of 2561261044 is about 1368.2053407720.

Adding to 2561261044 its reverse (4401621652), we get a palindrome (6962882696).

The spelling of 2561261044 in words is "two billion, five hundred sixty-one million, two hundred sixty-one thousand, forty-four".