123131221 has 8 divisors (see below), whose sum is σ = 131666904. Its totient is φ = 114739200.

The previous prime is 123131219. The next prime is 123131237. The reversal of 123131221 is 122131321.

It can be written as a sum of positive squares in 4 ways, for example, as 52403121 + 70728100 = 7239^2 + 8410^2 .

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 123131221 - 2¹ = 123131219 is a prime.

It is a super-2 number, since 2×123131221² = 30322595169901682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 123131195 and 123131204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123131251) 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, 34140 + ... + 37573.

It is an arithmetic number, because the mean of its divisors is an integer number (16458363).

Almost surely, 2^123131221 is an apocalyptic number.

It is an amenable number.

123131221 is a deficient number, since it is larger than the sum of its proper divisors (8535683).

123131221 is a wasteful number, since it uses less digits than its factorization.

123131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71831.

The product of its digits is 72, while the sum is 16.

The square root of 123131221 is about 11096.4508289813. The cubic root of 123131221 is about 497.4957733031.

Adding to 123131221 its reverse (122131321), we get a palindrome (245262542).

The spelling of 123131221 in words is "one hundred twenty-three million, one hundred thirty-one thousand, two hundred twenty-one".