1213121011 has 4 divisors (see below), whose sum is σ = 1254952800. Its totient is φ = 1171289224.

The previous prime is 1213121009. The next prime is 1213121017. The reversal of 1213121011 is 1101213121.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1213121011 - 2¹ = 1213121009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213120982 and 1213121000.

It is not an unprimeable number, because it can be changed into a prime (1213121017) 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, 20915851 + ... + 20915908.

It is an arithmetic number, because the mean of its divisors is an integer number (313738200).

Almost surely, 2^1213121011 is an apocalyptic number.

1213121011 is a deficient number, since it is larger than the sum of its proper divisors (41831789).

1213121011 is an equidigital number, since it uses as much as digits as its factorization.

1213121011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41831788.

The product of its (nonzero) digits is 12, while the sum is 13.

The square root of 1213121011 is about 34829.8867497441. The cubic root of 1213121011 is about 1066.5176364816.

Adding to 1213121011 its reverse (1101213121), we get a palindrome (2314334132).

The spelling of 1213121011 in words is "one billion, two hundred thirteen million, one hundred twenty-one thousand, eleven".