16904047681 has 4 divisors (see below), whose sum is σ = 17135610052. Its totient is φ = 16672485312.

The previous prime is 16904047651. The next prime is 16904047717. The reversal of 16904047681 is 18674040961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18674040961 = 131 ⋅142549931.

It can be written as a sum of positive squares in 2 ways, for example, as 9645007681 + 7259040000 = 98209^2 + 85200^2 .

It is a cyclic number.

It is not a de Polignac number, because 16904047681 - 2⁵ = 16904047649 is a prime.

It is a super-2 number, since 2×16904047681² (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 (16904047621) 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, 115781076 + ... + 115781221.

It is an arithmetic number, because the mean of its divisors is an integer number (4283902513).

Almost surely, 2^16904047681 is an apocalyptic number.

It is an amenable number.

16904047681 is a deficient number, since it is larger than the sum of its proper divisors (231562371).

16904047681 is an equidigital number, since it uses as much as digits as its factorization.

16904047681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231562370.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 16904047681 in words is "sixteen billion, nine hundred four million, forty-seven thousand, six hundred eighty-one".