131221805623 has 4 divisors (see below), whose sum is σ = 131549042448. Its totient is φ = 130894568800.

The previous prime is 131221805609. The next prime is 131221805629. The reversal of 131221805623 is 326508122131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 326508122131 = 109 ⋅2995487359.

It is a cyclic number.

It is not a de Polignac number, because 131221805623 - 2¹³ = 131221797431 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 (131221805629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163617811 + ... + 163618612.

It is an arithmetic number, because the mean of its divisors is an integer number (32887260612).

Almost surely, 2^131221805623 is an apocalyptic number.

131221805623 is a deficient number, since it is larger than the sum of its proper divisors (327236825).

131221805623 is an equidigital number, since it uses as much as digits as its factorization.

131221805623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327236824.

The product of its (nonzero) digits is 17280, while the sum is 34.

Adding to 131221805623 its reverse (326508122131), we get a palindrome (457729927754).

The spelling of 131221805623 in words is "one hundred thirty-one billion, two hundred twenty-one million, eight hundred five thousand, six hundred twenty-three".