1213031021 has 4 divisors (see below), whose sum is σ = 1217540700. Its totient is φ = 1208521344.

The previous prime is 1213030997. The next prime is 1213031059. The reversal of 1213031021 is 1201303121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1201303121 = 311 ⋅3862711.

It can be written as a sum of positive squares in 2 ways, for example, as 496665796 + 716365225 = 22286^2 + 26765^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213031021 - 2³⁰ = 139289197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213030987 and 1213031005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213031221) 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, 2254436 + ... + 2254973.

It is an arithmetic number, because the mean of its divisors is an integer number (304385175).

Almost surely, 2^1213031021 is an apocalyptic number.

It is an amenable number.

1213031021 is a deficient number, since it is larger than the sum of its proper divisors (4509679).

1213031021 is an equidigital number, since it uses as much as digits as its factorization.

1213031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4509678.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 1213031021 is about 34828.5948754755. The cubic root of 1213031021 is about 1066.4912642031.

Adding to 1213031021 its reverse (1201303121), we get a palindrome (2414334142).

The spelling of 1213031021 in words is "one billion, two hundred thirteen million, thirty-one thousand, twenty-one".