211220221391 has 2 divisors, whose sum is σ = 211220221392. Its totient is φ = 211220221390.

The previous prime is 211220221327. The next prime is 211220221411. The reversal of 211220221391 is 193122022112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211220221391 - 2⁶ = 211220221327 is a prime.

It is a super-2 number, since 2×211220221391² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 211220221391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211220221301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610110695 + 105610110696.

It is an arithmetic number, because the mean of its divisors is an integer number (105610110696).

Almost surely, 2^211220221391 is an apocalyptic number.

211220221391 is a deficient number, since it is larger than the sum of its proper divisors (1).

211220221391 is an equidigital number, since it uses as much as digits as its factorization.

211220221391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The spelling of 211220221391 in words is "two hundred eleven billion, two hundred twenty million, two hundred twenty-one thousand, three hundred ninety-one".