131223221021 has 4 divisors (see below), whose sum is σ = 131308933344. Its totient is φ = 131137508700.

The previous prime is 131223220963. The next prime is 131223221027. The reversal of 131223221021 is 120122322131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131223221021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131223220984 and 131223221002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131223221027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42853865 + ... + 42856926.

It is an arithmetic number, because the mean of its divisors is an integer number (32827233336).

Almost surely, 2^131223221021 is an apocalyptic number.

It is an amenable number.

131223221021 is a deficient number, since it is larger than the sum of its proper divisors (85712323).

131223221021 is an equidigital number, since it uses as much as digits as its factorization.

131223221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85712322.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 131223221021 its reverse (120122322131), we get a palindrome (251345543152).

The spelling of 131223221021 in words is "one hundred thirty-one billion, two hundred twenty-three million, two hundred twenty-one thousand, twenty-one".