2561651431111 has 4 divisors (see below), whose sum is σ = 2561698922224. Its totient is φ = 2561603940000.

The previous prime is 2561651431109. The next prime is 2561651431121. The reversal of 2561651431111 is 1111341561652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2561651431111 - 2¹ = 2561651431109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561651431121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23664555 + ... + 23772556.

It is an arithmetic number, because the mean of its divisors is an integer number (640424730556).

Almost surely, 2^{2561651431111} is an apocalyptic number.

2561651431111 is a deficient number, since it is larger than the sum of its proper divisors (47491113).

2561651431111 is an equidigital number, since it uses as much as digits as its factorization.

2561651431111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47491112.

The product of its digits is 21600, while the sum is 37.

Adding to 2561651431111 its reverse (1111341561652), we get a palindrome (3672992992763).

The spelling of 2561651431111 in words is "two trillion, five hundred sixty-one billion, six hundred fifty-one million, four hundred thirty-one thousand, one hundred eleven".