821215480181 has 4 divisors (see below), whose sum is σ = 829188446112. Its totient is φ = 813242514252.

The previous prime is 821215480159. The next prime is 821215480193. The reversal of 821215480181 is 181084512128.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 821215480181 - 2¹⁸ = 821215218037 is a prime.

It is a super-2 number, since 2×821215480181² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821215480081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3986482811 + ... + 3986483016.

It is an arithmetic number, because the mean of its divisors is an integer number (207297111528).

Almost surely, 2^821215480181 is an apocalyptic number.

It is an amenable number.

821215480181 is a deficient number, since it is larger than the sum of its proper divisors (7972965931).

821215480181 is a wasteful number, since it uses less digits than its factorization.

821215480181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7972965930.

The product of its (nonzero) digits is 40960, while the sum is 41.

The spelling of 821215480181 in words is "eight hundred twenty-one billion, two hundred fifteen million, four hundred eighty thousand, one hundred eighty-one".