215621321291 has 2 divisors, whose sum is σ = 215621321292. Its totient is φ = 215621321290.

The previous prime is 215621321269. The next prime is 215621321341. The reversal of 215621321291 is 192123126512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215621321291 is a prime.

It is not a weakly prime, because it can be changed into another prime (215621321891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107810660645 + 107810660646.

It is an arithmetic number, because the mean of its divisors is an integer number (107810660646).

Almost surely, 2^215621321291 is an apocalyptic number.

215621321291 is a deficient number, since it is larger than the sum of its proper divisors (1).

215621321291 is an equidigital number, since it uses as much as digits as its factorization.

215621321291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 35.

The spelling of 215621321291 in words is "two hundred fifteen billion, six hundred twenty-one million, three hundred twenty-one thousand, two hundred ninety-one".