261043507 has 4 divisors (see below), whose sum is σ = 261714960. Its totient is φ = 260372056.

The previous prime is 261043493. The next prime is 261043511. The reversal of 261043507 is 705340162.

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 261043507 - 2⁷ = 261043379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261043207) 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, 335143 + ... + 335920.

It is an arithmetic number, because the mean of its divisors is an integer number (65428740).

Almost surely, 2^261043507 is an apocalyptic number.

261043507 is a deficient number, since it is larger than the sum of its proper divisors (671453).

261043507 is an equidigital number, since it uses as much as digits as its factorization.

261043507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671452.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 261043507 is about 16156.8408731410. The cubic root of 261043507 is about 639.1031603388.

Adding to 261043507 its reverse (705340162), we get a palindrome (966383669).

The spelling of 261043507 in words is "two hundred sixty-one million, forty-three thousand, five hundred seven".