211751551997 has 2 divisors, whose sum is σ = 211751551998. Its totient is φ = 211751551996.

The previous prime is 211751551987. The next prime is 211751552029. The reversal of 211751551997 is 799155157112.

211751551997 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., 121930862596 + 89820689401 = 349186^2 + 299701^2 .

It is a cyclic number.

It is not a de Polignac number, because 211751551997 - 2¹⁴ = 211751535613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211751551987) 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, 105875775998 + 105875775999.

It is an arithmetic number, because the mean of its divisors is an integer number (105875775999).

Almost surely, 2^211751551997 is an apocalyptic number.

It is an amenable number.

211751551997 is a deficient number, since it is larger than the sum of its proper divisors (1).

211751551997 is an equidigital number, since it uses as much as digits as its factorization.

211751551997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 992250, while the sum is 53.

The spelling of 211751551997 in words is "two hundred eleven billion, seven hundred fifty-one million, five hundred fifty-one thousand, nine hundred ninety-seven".