261612231 has 4 divisors (see below), whose sum is σ = 348816312. Its totient is φ = 174408152.

The previous prime is 261612203. The next prime is 261612233. The reversal of 261612231 is 132216162.

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 261612231 - 2¹⁵ = 261579463 is a prime.

It is a super-2 number, since 2×261612231² = 136881918817594722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261612233) 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, 43602036 + ... + 43602041.

It is an arithmetic number, because the mean of its divisors is an integer number (87204078).

Almost surely, 2^261612231 is an apocalyptic number.

261612231 is a deficient number, since it is larger than the sum of its proper divisors (87204081).

261612231 is an equidigital number, since it uses as much as digits as its factorization.

261612231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87204080.

The product of its digits is 864, while the sum is 24.

The square root of 261612231 is about 16174.4313964974. The cubic root of 261612231 is about 639.5669523300.

Adding to 261612231 its reverse (132216162), we get a palindrome (393828393).

The spelling of 261612231 in words is "two hundred sixty-one million, six hundred twelve thousand, two hundred thirty-one".