261376643 has 8 divisors (see below), whose sum is σ = 289813296. Its totient is φ = 233719200.

The previous prime is 261376639. The next prime is 261376651. The reversal of 261376643 is 346673162.

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

It is not a de Polignac number, because 261376643 - 2² = 261376639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261376597 and 261376606.

It is not an unprimeable number, because it can be changed into a prime (261376613) 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, 194096 + ... + 195437.

It is an arithmetic number, because the mean of its divisors is an integer number (36226662).

Almost surely, 2^261376643 is an apocalyptic number.

261376643 is a deficient number, since it is larger than the sum of its proper divisors (28436653).

261376643 is a wasteful number, since it uses less digits than its factorization.

261376643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389605.

The product of its digits is 108864, while the sum is 38.

The square root of 261376643 is about 16167.1470272278. The cubic root of 261376643 is about 639.3749129519.

The spelling of 261376643 in words is "two hundred sixty-one million, three hundred seventy-six thousand, six hundred forty-three".