8436581821 has 2 divisors, whose sum is σ = 8436581822. Its totient is φ = 8436581820.

The previous prime is 8436581807. The next prime is 8436581941. The reversal of 8436581821 is 1281856348.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5838640921 + 2597940900 = 76411^2 + 50970^2 .

It is a cyclic number.

It is not a de Polignac number, because 8436581821 - 2¹¹ = 8436579773 is a prime.

It is a super-3 number, since 3×8436581821³ (a number of 31 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8436581801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4218290910 + 4218290911.

It is an arithmetic number, because the mean of its divisors is an integer number (4218290911).

Almost surely, 2^8436581821 is an apocalyptic number.

It is an amenable number.

8436581821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8436581821 is an equidigital number, since it uses as much as digits as its factorization.

8436581821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 368640, while the sum is 46.

The square root of 8436581821 is about 91850.8672849636. The cubic root of 8436581821 is about 2035.7393632117.

The spelling of 8436581821 in words is "eight billion, four hundred thirty-six million, five hundred eighty-one thousand, eight hundred twenty-one".