16720831 has 2 divisors, whose sum is σ = 16720832. Its totient is φ = 16720830.

The previous prime is 16720829. The next prime is 16720841. The reversal of 16720831 is 13802761.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16720831 - 2¹ = 16720829 is a prime.

It is a super-2 number, since 2×16720831² = 559172378661122, which contains 22 as substring.

Together with 16720829, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 16720831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16720841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360415 + 8360416.

It is an arithmetic number, because the mean of its divisors is an integer number (8360416).

Almost surely, 2^16720831 is an apocalyptic number.

16720831 is a deficient number, since it is larger than the sum of its proper divisors (1).

16720831 is an equidigital number, since it uses as much as digits as its factorization.

16720831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 16720831 is about 4089.1112726361. Note that the first 3 decimals coincide. The cubic root of 16720831 is about 255.7128891775.

The spelling of 16720831 in words is "sixteen million, seven hundred twenty thousand, eight hundred thirty-one".