261998167 has 4 divisors (see below), whose sum is σ = 264446856. Its totient is φ = 259549480.

The previous prime is 261998131. The next prime is 261998171. The reversal of 261998167 is 761899162.

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 261998167 - 2¹⁵ = 261965399 is a prime.

It is a super-2 number, since 2×261998167² = 137286079022719778, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261998167.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261992167) 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, 1224184 + ... + 1224397.

It is an arithmetic number, because the mean of its divisors is an integer number (66111714).

Almost surely, 2^261998167 is an apocalyptic number.

261998167 is a deficient number, since it is larger than the sum of its proper divisors (2448689).

261998167 is a wasteful number, since it uses less digits than its factorization.

261998167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2448688.

The product of its digits is 326592, while the sum is 49.

The square root of 261998167 is about 16186.3574345805. The cubic root of 261998167 is about 639.8812987866.

The spelling of 261998167 in words is "two hundred sixty-one million, nine hundred ninety-eight thousand, one hundred sixty-seven".