13121023221 has 40 divisors (see below), whose sum is σ = 19906214328. Its totient is φ = 8611920000.

The previous prime is 13121023207. The next prime is 13121023241. The reversal of 13121023221 is 12232012131.

13121023221 is a `hidden beast` number, since 131 + 210 + 2 + 322 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5254220196 + 7866803025 = 72486^2 + 88695^2 .

It is not a de Polignac number, because 13121023221 - 2¹³ = 13121015029 is a prime.

It is a super-2 number, since 2×13121023221² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13121023194 and 13121023203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121023241) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1476331 + ... + 1485191.

Almost surely, 2^13121023221 is an apocalyptic number.

It is an amenable number.

13121023221 is a deficient number, since it is larger than the sum of its proper divisors (6785191107).

13121023221 is a wasteful number, since it uses less digits than its factorization.

13121023221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9155 (or 9146 counting only the distinct ones).

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

Adding to 13121023221 its reverse (12232012131), we get a palindrome (25353035352).

The spelling of 13121023221 in words is "thirteen billion, one hundred twenty-one million, twenty-three thousand, two hundred twenty-one".