131223210021 has 12 divisors (see below), whose sum is σ = 189548287500. Its totient is φ = 87480455040.

The previous prime is 131223210007. The next prime is 131223210029. The reversal of 131223210021 is 120012322131.

131223210021 is a `hidden beast` number, since 1 + 312 + 232 + 100 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3870581796 + 127352628225 = 62214^2 + 356865^2 .

It is not a de Polignac number, because 131223210021 - 2¹⁰ = 131223208997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131223209976 and 131223210003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131223210029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 512701 + ... + 724781.

It is an arithmetic number, because the mean of its divisors is an integer number (15795690625).

Almost surely, 2^131223210021 is an apocalyptic number.

It is an amenable number.

131223210021 is a deficient number, since it is larger than the sum of its proper divisors (58325077479).

131223210021 is a wasteful number, since it uses less digits than its factorization.

131223210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280836 (or 280833 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 131223210021 its reverse (120012322131), we get a palindrome (251235532152).

The spelling of 131223210021 in words is "one hundred thirty-one billion, two hundred twenty-three million, two hundred ten thousand, twenty-one".