5661391871 has 2 divisors, whose sum is σ = 5661391872. Its totient is φ = 5661391870.

The previous prime is 5661391859. The next prime is 5661391873. The reversal of 5661391871 is 1781931665.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5661391871 is a prime.

Together with 5661391873, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5661391873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2830695935 + 2830695936.

It is an arithmetic number, because the mean of its divisors is an integer number (2830695936).

Almost surely, 2^5661391871 is an apocalyptic number.

5661391871 is a deficient number, since it is larger than the sum of its proper divisors (1).

5661391871 is an equidigital number, since it uses as much as digits as its factorization.

5661391871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 47.

The square root of 5661391871 is about 75242.2213321749. The cubic root of 5661391871 is about 1782.2737293557.

The spelling of 5661391871 in words is "five billion, six hundred sixty-one million, three hundred ninety-one thousand, eight hundred seventy-one".