8149818821 has 2 divisors, whose sum is σ = 8149818822. Its totient is φ = 8149818820.

The previous prime is 8149818667. The next prime is 8149818823. The reversal of 8149818821 is 1288189418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7026630625 + 1123188196 = 83825^2 + 33514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8149818821 is a prime.

It is a Sophie Germain prime.

Together with 8149818823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 8149818821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8149818823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4074909410 + 4074909411.

It is an arithmetic number, because the mean of its divisors is an integer number (4074909411).

Almost surely, 2^8149818821 is an apocalyptic number.

It is an amenable number.

8149818821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8149818821 is an equidigital number, since it uses as much as digits as its factorization.

8149818821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 294912, while the sum is 50.

The square root of 8149818821 is about 90276.3469630888. The cubic root of 8149818821 is about 2012.4077662345.

The spelling of 8149818821 in words is "eight billion, one hundred forty-nine million, eight hundred eighteen thousand, eight hundred twenty-one".