211521493 has 2 divisors, whose sum is σ = 211521494. Its totient is φ = 211521492.

The previous prime is 211521481. The next prime is 211521503. The reversal of 211521493 is 394125112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 190937124 + 20584369 = 13818^2 + 4537^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211521493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211521413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105760746 + 105760747.

It is an arithmetic number, because the mean of its divisors is an integer number (105760747).

Almost surely, 2^211521493 is an apocalyptic number.

It is an amenable number.

211521493 is a deficient number, since it is larger than the sum of its proper divisors (1).

211521493 is an equidigital number, since it uses as much as digits as its factorization.

211521493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 211521493 is about 14543.7784980383. The cubic root of 211521493 is about 595.8242400599.

The spelling of 211521493 in words is "two hundred eleven million, five hundred twenty-one thousand, four hundred ninety-three".