261306643 has 8 divisors (see below), whose sum is σ = 297960768. Its totient is φ = 227017344.

The previous prime is 261306631. The next prime is 261306671. The reversal of 261306643 is 346603162.

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 261306643 - 2⁹ = 261306131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261306613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 590971 + ... + 591412.

It is an arithmetic number, because the mean of its divisors is an integer number (37245096).

Almost surely, 2^261306643 is an apocalyptic number.

261306643 is a deficient number, since it is larger than the sum of its proper divisors (36654125).

261306643 is a wasteful number, since it uses less digits than its factorization.

261306643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182413.

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 261306643 is about 16164.9819981341. The cubic root of 261306643 is about 639.3178302692.

The spelling of 261306643 in words is "two hundred sixty-one million, three hundred six thousand, six hundred forty-three".