212516509 has 2 divisors, whose sum is σ = 212516510. Its totient is φ = 212516508.

The previous prime is 212516477. The next prime is 212516533. The reversal of 212516509 is 905615212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 186404409 + 26112100 = 13653^2 + 5110^2 .

It is a cyclic number.

It is not a de Polignac number, because 212516509 - 2⁵ = 212516477 is a prime.

It is a super-4 number, since 4×212516509⁴ (a number of 34 digits) contains 4444 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212516569) 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, 106258254 + 106258255.

It is an arithmetic number, because the mean of its divisors is an integer number (106258255).

Almost surely, 2^212516509 is an apocalyptic number.

It is an amenable number.

212516509 is a deficient number, since it is larger than the sum of its proper divisors (1).

212516509 is an equidigital number, since it uses as much as digits as its factorization.

212516509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 212516509 is about 14577.9459801441. The cubic root of 212516509 is about 596.7570490647.

The spelling of 212516509 in words is "two hundred twelve million, five hundred sixteen thousand, five hundred nine".