261912695791 has 4 divisors (see below), whose sum is σ = 262078150752. Its totient is φ = 261747240832.

The previous prime is 261912695717. The next prime is 261912695843. The reversal of 261912695791 is 197596219162.

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 261912695791 - 2⁷ = 261912695663 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261912695591) 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, 82725106 + ... + 82728271.

It is an arithmetic number, because the mean of its divisors is an integer number (65519537688).

Almost surely, 2^261912695791 is an apocalyptic number.

261912695791 is a deficient number, since it is larger than the sum of its proper divisors (165454961).

261912695791 is a wasteful number, since it uses less digits than its factorization.

261912695791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165454960.

The product of its digits is 3674160, while the sum is 58.

The spelling of 261912695791 in words is "two hundred sixty-one billion, nine hundred twelve million, six hundred ninety-five thousand, seven hundred ninety-one".