261192691 has 4 divisors (see below), whose sum is σ = 262560384. Its totient is φ = 259825000.

The previous prime is 261192689. The next prime is 261192697. The reversal of 261192691 is 196291162.

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 261192691 - 2¹ = 261192689 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 261192691.

It is not an unprimeable number, because it can be changed into a prime (261192697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 683560 + ... + 683941.

It is an arithmetic number, because the mean of its divisors is an integer number (65640096).

Almost surely, 2^261192691 is an apocalyptic number.

261192691 is a deficient number, since it is larger than the sum of its proper divisors (1367693).

261192691 is a wasteful number, since it uses less digits than its factorization.

261192691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1367692.

The product of its digits is 11664, while the sum is 37.

The square root of 261192691 is about 16161.4569578364. The cubic root of 261192691 is about 639.2248843763.

The spelling of 261192691 in words is "two hundred sixty-one million, one hundred ninety-two thousand, six hundred ninety-one".