16121204321 has 4 divisors (see below), whose sum is σ = 16822126272. Its totient is φ = 15420282372.

The previous prime is 16121204269. The next prime is 16121204339. The reversal of 16121204321 is 12340212161.

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 16121204321 - 2¹⁴ = 16121187937 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 700921927 = 16121204321 / (1 + 6 + 1 + 2 + 1 + 2 + 0 + 4 + 3 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16121204221) 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, 350460941 + ... + 350460986.

It is an arithmetic number, because the mean of its divisors is an integer number (4205531568).

Almost surely, 2^16121204321 is an apocalyptic number.

It is an amenable number.

16121204321 is a deficient number, since it is larger than the sum of its proper divisors (700921951).

16121204321 is an equidigital number, since it uses as much as digits as its factorization.

16121204321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700921950.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 16121204321 its reverse (12340212161), we get a palindrome (28461416482).

The spelling of 16121204321 in words is "sixteen billion, one hundred twenty-one million, two hundred four thousand, three hundred twenty-one".