261688047 has 8 divisors (see below), whose sum is σ = 350482944. Its totient is φ = 173675928.

The previous prime is 261688027. The next prime is 261688051. The reversal of 261688047 is 740886162.

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

It is not a de Polignac number, because 261688047 - 2¹⁸ = 261425903 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261688027) 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 7 ways as a sum of consecutive naturals, for example, 194913 + ... + 196250.

It is an arithmetic number, because the mean of its divisors is an integer number (43810368).

Almost surely, 2^261688047 is an apocalyptic number.

261688047 is a deficient number, since it is larger than the sum of its proper divisors (88794897).

261688047 is a wasteful number, since it uses less digits than its factorization.

261688047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391389.

The product of its (nonzero) digits is 129024, while the sum is 42.

The square root of 261688047 is about 16176.7749258003. The cubic root of 261688047 is about 639.6287291622.

The spelling of 261688047 in words is "two hundred sixty-one million, six hundred eighty-eight thousand, forty-seven".