131020805 has 6 divisors (see below), whose sum is σ = 157255686. Its totient is φ = 104796168.

The previous prime is 131020801. The next prime is 131020831. The reversal of 131020805 is 508020131.

It can be written as a sum of positive squares in only one way, i.e., 104816644 + 26204161 = 10238^2 + 5119^2 .

It is not a de Polignac number, because 131020805 - 2² = 131020801 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 (131020801) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23036 + ... + 28154.

It is an arithmetic number, because the mean of its divisors is an integer number (26209281).

Almost surely, 2^131020805 is an apocalyptic number.

It is an amenable number.

131020805 is a deficient number, since it is larger than the sum of its proper divisors (26234881).

131020805 is an frugal number, since it uses more digits than its factorization.

131020805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10243 (or 5124 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 131020805 is about 11446.4319768214. The cubic root of 131020805 is about 507.9021927661.

Multiplying 131020805 by its sum of digits (20), we get a square (2620416100 = 51190²).

Adding to 131020805 its reverse (508020131), we get a palindrome (639040936).

The spelling of 131020805 in words is "one hundred thirty-one million, twenty thousand, eight hundred five".