2561381738 has 8 divisors (see below), whose sum is σ = 4068076932. Its totient is φ = 1205356096.

The previous prime is 2561381699. The next prime is 2561381749. The reversal of 2561381738 is 8371831652.

It is a happy number.

2561381738 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 2226235489 + 335146249 = 47183^2 + 18307^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37667345 + ... + 37667412.

Almost surely, 2^2561381738 is an apocalyptic number.

2561381738 is a deficient number, since it is larger than the sum of its proper divisors (1506695194).

2561381738 is a wasteful number, since it uses less digits than its factorization.

2561381738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75334776.

The product of its digits is 241920, while the sum is 44.

The square root of 2561381738 is about 50610.0952182467. The cubic root of 2561381738 is about 1368.2268316937.

The spelling of 2561381738 in words is "two billion, five hundred sixty-one million, three hundred eighty-one thousand, seven hundred thirty-eight".