261772171 has 4 divisors (see below), whose sum is σ = 277170552. Its totient is φ = 246373792.

The previous prime is 261772117. The next prime is 261772211. The reversal of 261772171 is 171277162.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 261772171 - 2¹¹ = 261770123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261772271) 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, 7699165 + ... + 7699198.

It is an arithmetic number, because the mean of its divisors is an integer number (69292638).

Almost surely, 2^261772171 is an apocalyptic number.

261772171 is a deficient number, since it is larger than the sum of its proper divisors (15398381).

261772171 is a wasteful number, since it uses less digits than its factorization.

261772171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15398380.

The product of its digits is 8232, while the sum is 34.

The square root of 261772171 is about 16179.3748643141. The cubic root of 261772171 is about 639.6972616038.

The spelling of 261772171 in words is "two hundred sixty-one million, seven hundred seventy-two thousand, one hundred seventy-one".