261404492911 has 4 divisors (see below), whose sum is σ = 262576710592. Its totient is φ = 260232275232.

The previous prime is 261404492893. The next prime is 261404492917. The reversal of 261404492911 is 119294404162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 119294404162 = 2 ⋅59647202081.

It is a cyclic number.

It is not a de Polignac number, because 261404492911 - 2²¹ = 261402395759 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 (261404492917) 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, 586108506 + ... + 586108951.

It is an arithmetic number, because the mean of its divisors is an integer number (65644177648).

Almost surely, 2^261404492911 is an apocalyptic number.

261404492911 is a deficient number, since it is larger than the sum of its proper divisors (1172217681).

261404492911 is a wasteful number, since it uses less digits than its factorization.

261404492911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172217680.

The product of its (nonzero) digits is 124416, while the sum is 43.

The spelling of 261404492911 in words is "two hundred sixty-one billion, four hundred four million, four hundred ninety-two thousand, nine hundred eleven".