16781791331 has 8 divisors (see below), whose sum is σ = 17378961600. Its totient is φ = 16194025512.

The previous prime is 16781791321. The next prime is 16781791333. The reversal of 16781791331 is 13319718761.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16781791331 - 2²² = 16777597027 is a prime.

It is a super-2 number, since 2×16781791331² (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 (16781791333) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2347481 + ... + 2354618.

It is an arithmetic number, because the mean of its divisors is an integer number (2172370200).

Almost surely, 2^16781791331 is an apocalyptic number.

16781791331 is a deficient number, since it is larger than the sum of its proper divisors (597170269).

16781791331 is an equidigital number, since it uses as much as digits as its factorization.

16781791331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4702225.

The product of its digits is 190512, while the sum is 47.

The spelling of 16781791331 in words is "sixteen billion, seven hundred eighty-one million, seven hundred ninety-one thousand, three hundred thirty-one".