71561780057111 has 4 divisors (see below), whose sum is σ = 71816448313824. Its totient is φ = 71307111800400.

The previous prime is 71561780056973. The next prime is 71561780057123. The reversal of 71561780057111 is 11175008716517.

It is a happy number.

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 71561780057111 - 2²⁶ = 71561712948247 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71561780057111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71561780057161) 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, 127334127935 + ... + 127334128496.

It is an arithmetic number, because the mean of its divisors is an integer number (17954112078456).

Almost surely, 2^{71561780057111} is an apocalyptic number.

71561780057111 is a deficient number, since it is larger than the sum of its proper divisors (254668256713).

71561780057111 is a wasteful number, since it uses less digits than its factorization.

71561780057111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254668256712.

The product of its (nonzero) digits is 411600, while the sum is 50.

The spelling of 71561780057111 in words is "seventy-one trillion, five hundred sixty-one billion, seven hundred eighty million, fifty-seven thousand, one hundred eleven".