16551537899 has 4 divisors (see below), whose sum is σ = 17824733136. Its totient is φ = 15278342664.

The previous prime is 16551537881. The next prime is 16551537917. The reversal of 16551537899 is 99873515561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99873515561 = 19 ⋅5256500819.

It is an interprime number because it is at equal distance from previous prime (16551537881) and next prime (16551537917).

It is not a de Polignac number, because 16551537899 - 2²⁰ = 16550489323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16551537809) 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, 636597599 + ... + 636597624.

It is an arithmetic number, because the mean of its divisors is an integer number (4456183284).

Almost surely, 2^16551537899 is an apocalyptic number.

16551537899 is a deficient number, since it is larger than the sum of its proper divisors (1273195237).

16551537899 is a wasteful number, since it uses less digits than its factorization.

16551537899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273195236.

The product of its digits is 10206000, while the sum is 59.

The spelling of 16551537899 in words is "sixteen billion, five hundred fifty-one million, five hundred thirty-seven thousand, eight hundred ninety-nine".