15991114421 has 4 divisors (see below), whose sum is σ = 16381141644. Its totient is φ = 15601087200.

The previous prime is 15991114411. The next prime is 15991114429. The reversal of 15991114421 is 12441119951.

15991114421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12441119951 = 13 ⋅957009227.

It can be written as a sum of positive squares in 2 ways, for example, as 3494110321 + 12497004100 = 59111^2 + 111790^2 .

It is a cyclic number.

It is not a de Polignac number, because 15991114421 - 2⁶ = 15991114357 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 (15991114429) 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, 195013550 + ... + 195013631.

It is an arithmetic number, because the mean of its divisors is an integer number (4095285411).

Almost surely, 2^15991114421 is an apocalyptic number.

It is an amenable number.

15991114421 is a deficient number, since it is larger than the sum of its proper divisors (390027223).

15991114421 is an equidigital number, since it uses as much as digits as its factorization.

15991114421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390027222.

The product of its digits is 12960, while the sum is 38.

The spelling of 15991114421 in words is "fifteen billion, nine hundred ninety-one million, one hundred fourteen thousand, four hundred twenty-one".