16821415181 has 2 divisors, whose sum is σ = 16821415182. Its totient is φ = 16821415180.

The previous prime is 16821415159. The next prime is 16821415189. The reversal of 16821415181 is 18151412861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9516978025 + 7304437156 = 97555^2 + 85466^2 .

It is a cyclic number.

It is not a de Polignac number, because 16821415181 - 2¹⁰ = 16821414157 is a prime.

It is a super-2 number, since 2×16821415181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16821415189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8410707590 + 8410707591.

It is an arithmetic number, because the mean of its divisors is an integer number (8410707591).

Almost surely, 2^16821415181 is an apocalyptic number.

It is an amenable number.

16821415181 is a deficient number, since it is larger than the sum of its proper divisors (1).

16821415181 is an equidigital number, since it uses as much as digits as its factorization.

16821415181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15360, while the sum is 38.

The spelling of 16821415181 in words is "sixteen billion, eight hundred twenty-one million, four hundred fifteen thousand, one hundred eighty-one".