861511254311 has 4 divisors (see below), whose sum is σ = 898968265392. Its totient is φ = 824054243232.

The previous prime is 861511254281. The next prime is 861511254367. The reversal of 861511254311 is 113452115168.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861511254311 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 (861511254211) 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, 18728505506 + ... + 18728505551.

It is an arithmetic number, because the mean of its divisors is an integer number (224742066348).

Almost surely, 2^861511254311 is an apocalyptic number.

861511254311 is a deficient number, since it is larger than the sum of its proper divisors (37457011081).

861511254311 is a wasteful number, since it uses less digits than its factorization.

861511254311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37457011080.

The product of its digits is 28800, while the sum is 38.

Adding to 861511254311 its reverse (113452115168), we get a palindrome (974963369479).

The spelling of 861511254311 in words is "eight hundred sixty-one billion, five hundred eleven million, two hundred fifty-four thousand, three hundred eleven".