131220309 has 16 divisors (see below), whose sum is σ = 192245760. Its totient is φ = 78952560.

The previous prime is 131220293. The next prime is 131220329. The reversal of 131220309 is 903022131.

It is a happy number.

It is not a de Polignac number, because 131220309 - 2⁴ = 131220293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131220329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9717 + ... + 18890.

It is an arithmetic number, because the mean of its divisors is an integer number (12015360).

Almost surely, 2^131220309 is an apocalyptic number.

It is an amenable number.

131220309 is a deficient number, since it is larger than the sum of its proper divisors (61025451).

131220309 is a wasteful number, since it uses less digits than its factorization.

131220309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28760.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 131220309 is about 11455.1433426213. The cubic root of 131220309 is about 508.1598544708.

The spelling of 131220309 in words is "one hundred thirty-one million, two hundred twenty thousand, three hundred nine".