261777171871 has 2 divisors, whose sum is σ = 261777171872. Its totient is φ = 261777171870.

The previous prime is 261777171857. The next prime is 261777171883. The reversal of 261777171871 is 178171777162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261777171871 - 2¹⁵ = 261777139103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261777171811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130888585935 + 130888585936.

It is an arithmetic number, because the mean of its divisors is an integer number (130888585936).

Almost surely, 2^261777171871 is an apocalyptic number.

261777171871 is a deficient number, since it is larger than the sum of its proper divisors (1).

261777171871 is an equidigital number, since it uses as much as digits as its factorization.

261777171871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1613472, while the sum is 55.

The spelling of 261777171871 in words is "two hundred sixty-one billion, seven hundred seventy-seven million, one hundred seventy-one thousand, eight hundred seventy-one".