16501631809 has 4 divisors (see below), whose sum is σ = 17770988116. Its totient is φ = 15232275504.

The previous prime is 16501631807. The next prime is 16501631849. The reversal of 16501631809 is 90813610561.

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 2530391809 + 13971240000 = 50303^2 + 118200^2 .

It is a cyclic number.

It is not a de Polignac number, because 16501631809 - 2¹ = 16501631807 is a prime.

It is a super-2 number, since 2×16501631809² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16501631801) 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, 634678134 + ... + 634678159.

It is an arithmetic number, because the mean of its divisors is an integer number (4442747029).

Almost surely, 2^16501631809 is an apocalyptic number.

It is an amenable number.

16501631809 is a deficient number, since it is larger than the sum of its proper divisors (1269356307).

16501631809 is a wasteful number, since it uses less digits than its factorization.

16501631809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1269356306.

The product of its (nonzero) digits is 38880, while the sum is 40.

The spelling of 16501631809 in words is "sixteen billion, five hundred one million, six hundred thirty-one thousand, eight hundred nine".