121216813 has 4 divisors (see below), whose sum is σ = 121851648. Its totient is φ = 120581980.

The previous prime is 121216811. The next prime is 121216853. The reversal of 121216813 is 318612121.

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 121216813 - 2¹ = 121216811 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121216811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 317131 + ... + 317512.

It is an arithmetic number, because the mean of its divisors is an integer number (30462912).

Almost surely, 2^121216813 is an apocalyptic number.

It is an amenable number.

121216813 is a deficient number, since it is larger than the sum of its proper divisors (634835).

121216813 is an equidigital number, since it uses as much as digits as its factorization.

121216813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634834.

The product of its digits is 576, while the sum is 25.

The square root of 121216813 is about 11009.8507256002. The cubic root of 121216813 is about 494.9039884527.

Adding to 121216813 its reverse (318612121), we get a palindrome (439828934).

The spelling of 121216813 in words is "one hundred twenty-one million, two hundred sixteen thousand, eight hundred thirteen".