211257256709 has 2 divisors, whose sum is σ = 211257256710. Its totient is φ = 211257256708.

The previous prime is 211257256657. The next prime is 211257256733. The reversal of 211257256709 is 907652752112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191087008225 + 20170248484 = 437135^2 + 142022^2 .

It is a cyclic number.

It is not a de Polignac number, because 211257256709 - 2⁸ = 211257256453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211257256799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105628628354 + 105628628355.

It is an arithmetic number, because the mean of its divisors is an integer number (105628628355).

Almost surely, 2^211257256709 is an apocalyptic number.

It is an amenable number.

211257256709 is a deficient number, since it is larger than the sum of its proper divisors (1).

211257256709 is an equidigital number, since it uses as much as digits as its factorization.

211257256709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 529200, while the sum is 47.

The spelling of 211257256709 in words is "two hundred eleven billion, two hundred fifty-seven million, two hundred fifty-six thousand, seven hundred nine".