1231232021221 has 4 divisors (see below), whose sum is σ = 1303657434252. Its totient is φ = 1158806608192.

The previous prime is 1231232021179. The next prime is 1231232021233. The reversal of 1231232021221 is 1221202321321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 407185648321 + 824046372900 = 638111^2 + 907770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231232021221 - 2⁷ = 1231232021093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231232021192 and 1231232021201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231232021291) 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, 36212706490 + ... + 36212706523.

It is an arithmetic number, because the mean of its divisors is an integer number (325914358563).

Almost surely, 2^{1231232021221} is an apocalyptic number.

It is an amenable number.

1231232021221 is a deficient number, since it is larger than the sum of its proper divisors (72425413031).

1231232021221 is an equidigital number, since it uses as much as digits as its factorization.

1231232021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72425413030.

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 1231232021221 its reverse (1221202321321), we get a palindrome (2452434342542).

The spelling of 1231232021221 in words is "one trillion, two hundred thirty-one billion, two hundred thirty-two million, twenty-one thousand, two hundred twenty-one".