16804237781 has 4 divisors (see below), whose sum is σ = 16819613292. Its totient is φ = 16788862272.

The previous prime is 16804237763. The next prime is 16804237787. The reversal of 16804237781 is 18773240861.

It is a happy number.

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 12014352100 + 4789885681 = 109610^2 + 69209^2 .

It is a cyclic number.

It is not a de Polignac number, because 16804237781 - 2²⁶ = 16737128917 is a prime.

It is a super-2 number, since 2×16804237781² (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 (16804237787) 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, 7686116 + ... + 7688301.

It is an arithmetic number, because the mean of its divisors is an integer number (4204903323).

Almost surely, 2^16804237781 is an apocalyptic number.

It is an amenable number.

16804237781 is a deficient number, since it is larger than the sum of its proper divisors (15375511).

16804237781 is a wasteful number, since it uses less digits than its factorization.

16804237781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15375510.

The product of its (nonzero) digits is 451584, while the sum is 47.

The spelling of 16804237781 in words is "sixteen billion, eight hundred four million, two hundred thirty-seven thousand, seven hundred eighty-one".