16813681 has 2 divisors, whose sum is σ = 16813682. Its totient is φ = 16813680.

The previous prime is 16813679. The next prime is 16813691. The reversal of 16813681 is 18631861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16646400 + 167281 = 4080^2 + 409^2 .

It is an emirp because it is prime and its reverse (18631861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16813681 - 2¹ = 16813679 is a prime.

It is a super-2 number, since 2×16813681² = 565399737539522, which contains 22 as substring.

Together with 16813679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16813631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8406840 + 8406841.

It is an arithmetic number, because the mean of its divisors is an integer number (8406841).

Almost surely, 2^16813681 is an apocalyptic number.

It is an amenable number.

16813681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16813681 is an equidigital number, since it uses as much as digits as its factorization.

16813681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 34.

The square root of 16813681 is about 4100.4488778669. The cubic root of 16813681 is about 256.1853363707.

The spelling of 16813681 in words is "sixteen million, eight hundred thirteen thousand, six hundred eighty-one".