261971671 has 4 divisors (see below), whose sum is σ = 282123352. Its totient is φ = 241819992.

The previous prime is 261971627. The next prime is 261971681. The reversal of 261971671 is 176179162.

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 261971671 - 2⁷ = 261971543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261971621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10075821 + ... + 10075846.

It is an arithmetic number, because the mean of its divisors is an integer number (70530838).

Almost surely, 2^261971671 is an apocalyptic number.

261971671 is a deficient number, since it is larger than the sum of its proper divisors (20151681).

261971671 is a wasteful number, since it uses less digits than its factorization.

261971671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20151680.

The product of its digits is 31752, while the sum is 40.

The square root of 261971671 is about 16185.5389468501. The cubic root of 261971671 is about 639.8597275587.

The spelling of 261971671 in words is "two hundred sixty-one million, nine hundred seventy-one thousand, six hundred seventy-one".