12121111621 has 4 divisors (see below), whose sum is σ = 12122067532. Its totient is φ = 12120155712.

The previous prime is 12121111609. The next prime is 12121111627. The reversal of 12121111621 is 12611112121.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8338246596 + 3782865025 = 91314^2 + 61505^2 .

It is a cyclic number.

It is not a de Polignac number, because 12121111621 - 2¹¹ = 12121109573 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 (12121111627) 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, 458676 + ... + 484381.

It is an arithmetic number, because the mean of its divisors is an integer number (3030516883).

Almost surely, 2^12121111621 is an apocalyptic number.

It is an amenable number.

12121111621 is a deficient number, since it is larger than the sum of its proper divisors (955911).

12121111621 is an equidigital number, since it uses as much as digits as its factorization.

12121111621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 955910.

The product of its digits is 48, while the sum is 19.

Adding to 12121111621 its reverse (12611112121), we get a palindrome (24732223742).

The spelling of 12121111621 in words is "twelve billion, one hundred twenty-one million, one hundred eleven thousand, six hundred twenty-one".