261242231 has 4 divisors (see below), whose sum is σ = 262972464. Its totient is φ = 259512000.

The previous prime is 261242221. The next prime is 261242263. The reversal of 261242231 is 132242162.

It is a happy number.

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 261242231 - 2⁶ = 261242167 is a prime.

It is a super-2 number, since 2×261242231² = 136495006515714722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261242197 and 261242206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261242221) 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, 864890 + ... + 865191.

It is an arithmetic number, because the mean of its divisors is an integer number (65743116).

Almost surely, 2^261242231 is an apocalyptic number.

261242231 is a deficient number, since it is larger than the sum of its proper divisors (1730233).

261242231 is a wasteful number, since it uses less digits than its factorization.

261242231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1730232.

The product of its digits is 1152, while the sum is 23.

The square root of 261242231 is about 16162.9895440169. The cubic root of 261242231 is about 639.2652954087.

Adding to 261242231 its reverse (132242162), we get a palindrome (393484393).

The spelling of 261242231 in words is "two hundred sixty-one million, two hundred forty-two thousand, two hundred thirty-one".