261161643 has 8 divisors (see below), whose sum is σ = 353120256. Its totient is φ = 171655400.

The previous prime is 261161629. The next prime is 261161683. The reversal of 261161643 is 346161162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261161643 - 2⁴ = 261161627 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261161643.

It is not an unprimeable number, because it can be changed into a prime (261161623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 612843 + ... + 613268.

It is an arithmetic number, because the mean of its divisors is an integer number (44140032).

Almost surely, 2^261161643 is an apocalyptic number.

261161643 is a deficient number, since it is larger than the sum of its proper divisors (91958613).

261161643 is a wasteful number, since it uses less digits than its factorization.

261161643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226185.

The product of its digits is 5184, while the sum is 30.

The square root of 261161643 is about 16160.4963723272. The cubic root of 261161643 is about 639.1995551317.

The spelling of 261161643 in words is "two hundred sixty-one million, one hundred sixty-one thousand, six hundred forty-three".