131579821 has 8 divisors (see below), whose sum is σ = 133721784. Its totient is φ = 129454080.

The previous prime is 131579809. The next prime is 131579839. The reversal of 131579821 is 128975131.

It can be written as a sum of positive squares in 4 ways, for example, as 33767721 + 97812100 = 5811^2 + 9890^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 131579821 - 2⁹ = 131579309 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 (131579891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12861 + ... + 20701.

It is an arithmetic number, because the mean of its divisors is an integer number (16715223).

Almost surely, 2^131579821 is an apocalyptic number.

It is an amenable number.

131579821 is a deficient number, since it is larger than the sum of its proper divisors (2141963).

131579821 is an equidigital number, since it uses as much as digits as its factorization.

131579821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8111.

The product of its digits is 15120, while the sum is 37.

The square root of 131579821 is about 11470.8247741825. The cubic root of 131579821 is about 508.6235097761.

The spelling of 131579821 in words is "one hundred thirty-one million, five hundred seventy-nine thousand, eight hundred twenty-one".