12121351021 has 8 divisors (see below), whose sum is σ = 13055812280. Its totient is φ = 11187182592.

The previous prime is 12121350991. The next prime is 12121351079. The reversal of 12121351021 is 12015312121.

It can be written as a sum of positive squares in 4 ways, for example, as 1397712996 + 10723638025 = 37386^2 + 103555^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12121351021 - 2¹⁹ = 12120826733 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12121351021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12821351021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16885 + ... + 156613.

It is an arithmetic number, because the mean of its divisors is an integer number (1631976535).

Almost surely, 2^12121351021 is an apocalyptic number.

It is an amenable number.

12121351021 is a deficient number, since it is larger than the sum of its proper divisors (934461259).

12121351021 is a wasteful number, since it uses less digits than its factorization.

12121351021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146415.

The product of its (nonzero) digits is 120, while the sum is 19.

Adding to 12121351021 its reverse (12015312121), we get a palindrome (24136663142).

The spelling of 12121351021 in words is "twelve billion, one hundred twenty-one million, three hundred fifty-one thousand, twenty-one".