261242143 has 4 divisors (see below), whose sum is σ = 261283680. Its totient is φ = 261200608.

The previous prime is 261242129. The next prime is 261242167. The reversal of 261242143 is 341242162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261242143 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 (261242123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9178 + ... + 24631.

It is an arithmetic number, because the mean of its divisors is an integer number (65320920).

Almost surely, 2^261242143 is an apocalyptic number.

261242143 is a deficient number, since it is larger than the sum of its proper divisors (41537).

261242143 is an equidigital number, since it uses as much as digits as its factorization.

261242143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41536.

The product of its digits is 2304, while the sum is 25.

The square root of 261242143 is about 16162.9868217480. The cubic root of 261242143 is about 639.2652236294.

The spelling of 261242143 in words is "two hundred sixty-one million, two hundred forty-two thousand, one hundred forty-three".