215621321311 has 12 divisors (see below), whose sum is σ = 247309833456. Its totient is φ = 187496798720.

The previous prime is 215621321291. The next prime is 215621321341. The reversal of 215621321311 is 113123126512.

It is not a de Polignac number, because 215621321311 - 2⁷ = 215621321183 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 215621321311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215621321341) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38736226 + ... + 38741791.

It is an arithmetic number, because the mean of its divisors is an integer number (20609152788).

Almost surely, 2^215621321311 is an apocalyptic number.

215621321311 is a deficient number, since it is larger than the sum of its proper divisors (31688512145).

215621321311 is a wasteful number, since it uses less digits than its factorization.

215621321311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77478062 (or 77478051 counting only the distinct ones).

The product of its digits is 2160, while the sum is 28.

Adding to 215621321311 its reverse (113123126512), we get a palindrome (328744447823).

The spelling of 215621321311 in words is "two hundred fifteen billion, six hundred twenty-one million, three hundred twenty-one thousand, three hundred eleven".