1213231021 has 4 divisors (see below), whose sum is σ = 1216727712. Its totient is φ = 1209734332.

The previous prime is 1213231009. The next prime is 1213231039. The reversal of 1213231021 is 1201323121.

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 not a de Polignac number, because 1213231021 - 2⁵ = 1213230989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213230986 and 1213231004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213234021) 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, 1747825 + ... + 1748518.

It is an arithmetic number, because the mean of its divisors is an integer number (304181928).

Almost surely, 2^1213231021 is an apocalyptic number.

It is an amenable number.

1213231021 is a deficient number, since it is larger than the sum of its proper divisors (3496691).

1213231021 is an equidigital number, since it uses as much as digits as its factorization.

1213231021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3496690.

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

The square root of 1213231021 is about 34831.4659611105. The cubic root of 1213231021 is about 1066.5498740072.

Adding to 1213231021 its reverse (1201323121), we get a palindrome (2414554142).

The spelling of 1213231021 in words is "one billion, two hundred thirteen million, two hundred thirty-one thousand, twenty-one".