261634343 has 4 divisors (see below), whose sum is σ = 264786648. Its totient is φ = 258482040.

The previous prime is 261634337. The next prime is 261634357. The reversal of 261634343 is 343436162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 343436162 = 2 ⋅171718081.

It is a cyclic number.

It is not a de Polignac number, because 261634343 - 2¹⁰ = 261633319 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 (261634393) 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, 1576028 + ... + 1576193.

It is an arithmetic number, because the mean of its divisors is an integer number (66196662).

Almost surely, 2^261634343 is an apocalyptic number.

261634343 is a deficient number, since it is larger than the sum of its proper divisors (3152305).

261634343 is an equidigital number, since it uses as much as digits as its factorization.

261634343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3152304.

The product of its digits is 31104, while the sum is 32.

The square root of 261634343 is about 16175.1149300399. The cubic root of 261634343 is about 639.5849709906.

The spelling of 261634343 in words is "two hundred sixty-one million, six hundred thirty-four thousand, three hundred forty-three".