1213012121 has 4 divisors (see below), whose sum is σ = 1225022244. Its totient is φ = 1201002000.

The previous prime is 1213012109. The next prime is 1213012133. The reversal of 1213012121 is 1212103121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1212103121 = 101 ⋅12001021.

It is an interprime number because it is at equal distance from previous prime (1213012109) and next prime (1213012133).

It can be written as a sum of positive squares in 2 ways, for example, as 1011939721 + 201072400 = 31811^2 + 14180^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213012121 - 2¹⁰ = 1213011097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213012096 and 1213012105.

It is not an unprimeable number, because it can be changed into a prime (1213012621) 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, 6004910 + ... + 6005111.

It is an arithmetic number, because the mean of its divisors is an integer number (306255561).

Almost surely, 2^1213012121 is an apocalyptic number.

It is an amenable number.

1213012121 is a deficient number, since it is larger than the sum of its proper divisors (12010123).

1213012121 is a wasteful number, since it uses less digits than its factorization.

1213012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12010122.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1213012121 is about 34828.3235456431. The cubic root of 1213012121 is about 1066.4857252435.

Adding to 1213012121 its reverse (1212103121), we get a palindrome (2425115242).

The spelling of 1213012121 in words is "one billion, two hundred thirteen million, twelve thousand, one hundred twenty-one".