131123261 has 4 divisors (see below), whose sum is σ = 138836412. Its totient is φ = 123410112.

The previous prime is 131123249. The next prime is 131123269. The reversal of 131123261 is 162321131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 162321131 = 7 ⋅23188733.

It can be written as a sum of positive squares in 2 ways, for example, as 47748100 + 83375161 = 6910^2 + 9131^2 .

It is a cyclic number.

It is not a de Polignac number, because 131123261 - 2²² = 126928957 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 (131123269) 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, 3856550 + ... + 3856583.

It is an arithmetic number, because the mean of its divisors is an integer number (34709103).

Almost surely, 2^131123261 is an apocalyptic number.

It is an amenable number.

131123261 is a deficient number, since it is larger than the sum of its proper divisors (7713151).

131123261 is an equidigital number, since it uses as much as digits as its factorization.

131123261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7713150.

The product of its digits is 216, while the sum is 20.

The square root of 131123261 is about 11450.9065579979. The cubic root of 131123261 is about 508.0345485111.

Adding to 131123261 its reverse (162321131), we get a palindrome (293444392).

The spelling of 131123261 in words is "one hundred thirty-one million, one hundred twenty-three thousand, two hundred sixty-one".