16485657991 has 4 divisors (see below), whose sum is σ = 17984354184. Its totient is φ = 14986961800.

The previous prime is 16485657973. The next prime is 16485658019. The reversal of 16485657991 is 19975658461.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16485657991 - 2⁷ = 16485657863 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 (16485657901) 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, 749348080 + ... + 749348101.

It is an arithmetic number, because the mean of its divisors is an integer number (4496088546).

Almost surely, 2^16485657991 is an apocalyptic number.

16485657991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16485657991 is a deficient number, since it is larger than the sum of its proper divisors (1498696193).

16485657991 is a wasteful number, since it uses less digits than its factorization.

16485657991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1498696192.

The product of its digits is 16329600, while the sum is 61.

It can be divided in two parts, 16485 and 657991, that added together give a palindrome (674476).

The spelling of 16485657991 in words is "sixteen billion, four hundred eighty-five million, six hundred fifty-seven thousand, nine hundred ninety-one".