215231155021 has 2 divisors, whose sum is σ = 215231155022. Its totient is φ = 215231155020.

The previous prime is 215231155003. The next prime is 215231155063. The reversal of 215231155021 is 120551132512.

It is a happy number.

215231155021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 172545528996 + 42685626025 = 415386^2 + 206605^2 .

It is a cyclic number.

It is not a de Polignac number, because 215231155021 - 2⁵ = 215231154989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215231155091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107615577510 + 107615577511.

It is an arithmetic number, because the mean of its divisors is an integer number (107615577511).

Almost surely, 2^215231155021 is an apocalyptic number.

It is an amenable number.

215231155021 is a deficient number, since it is larger than the sum of its proper divisors (1).

215231155021 is an equidigital number, since it uses as much as digits as its factorization.

215231155021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3000, while the sum is 28.

Adding to 215231155021 its reverse (120551132512), we get a palindrome (335782287533).

The spelling of 215231155021 in words is "two hundred fifteen billion, two hundred thirty-one million, one hundred fifty-five thousand, twenty-one".