131121665 has 4 divisors (see below), whose sum is σ = 157346004. Its totient is φ = 104897328.

The previous prime is 131121637. The next prime is 131121701. The reversal of 131121665 is 566121131.

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

It can be written as a sum of positive squares in 2 ways, for example, as 96746896 + 34374769 = 9836^2 + 5863^2 .

It is a cyclic number.

It is not a de Polignac number, because 131121665 - 2⁸ = 131121409 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13112162 + ... + 13112171.

It is an arithmetic number, because the mean of its divisors is an integer number (39336501).

Almost surely, 2^131121665 is an apocalyptic number.

It is an amenable number.

131121665 is a deficient number, since it is larger than the sum of its proper divisors (26224339).

131121665 is an equidigital number, since it uses as much as digits as its factorization.

131121665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26224338.

The product of its digits is 1080, while the sum is 26.

The square root of 131121665 is about 11450.8368689804. The cubic root of 131121665 is about 508.0324872790.

Adding to 131121665 its reverse (566121131), we get a palindrome (697242796).

The spelling of 131121665 in words is "one hundred thirty-one million, one hundred twenty-one thousand, six hundred sixty-five".