131506809 has 16 divisors (see below), whose sum is σ = 210938880. Its totient is φ = 71191440.

The previous prime is 131506807. The next prime is 131506819. The reversal of 131506809 is 908605131.

It is not a de Polignac number, because 131506809 - 2¹ = 131506807 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 131506809.

It is not an unprimeable number, because it can be changed into a prime (131506807) 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, 164397 + ... + 165194.

It is an arithmetic number, because the mean of its divisors is an integer number (13183680).

Almost surely, 2^131506809 is an apocalyptic number.

131506809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

131506809 is a deficient number, since it is larger than the sum of its proper divisors (79432071).

131506809 is a wasteful number, since it uses less digits than its factorization.

131506809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329620.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 131506809 is about 11467.6418238450. The cubic root of 131506809 is about 508.5294160916.

The spelling of 131506809 in words is "one hundred thirty-one million, five hundred six thousand, eight hundred nine".