16399973431 has 4 divisors (see below), whose sum is σ = 16929004864. Its totient is φ = 15870942000.

The previous prime is 16399973417. The next prime is 16399973437. The reversal of 16399973431 is 13437999361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13437999361 = 233 ⋅57673817.

It is a cyclic number.

It is not a de Polignac number, because 16399973431 - 2⁵ = 16399973399 is a prime.

It is a super-2 number, since 2×16399973431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16399973437) 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 3 ways as a sum of consecutive naturals, for example, 264515670 + ... + 264515731.

It is an arithmetic number, because the mean of its divisors is an integer number (4232251216).

Almost surely, 2^16399973431 is an apocalyptic number.

16399973431 is a deficient number, since it is larger than the sum of its proper divisors (529031433).

16399973431 is an equidigital number, since it uses as much as digits as its factorization.

16399973431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529031432.

The product of its digits is 3306744, while the sum is 55.

The spelling of 16399973431 in words is "sixteen billion, three hundred ninety-nine million, nine hundred seventy-three thousand, four hundred thirty-one".