212581813 has 2 divisors, whose sum is σ = 212581814. Its totient is φ = 212581812.

The previous prime is 212581793. The next prime is 212581879. The reversal of 212581813 is 318185212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 176305284 + 36276529 = 13278^2 + 6023^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212581813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212581883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106290906 + 106290907.

It is an arithmetic number, because the mean of its divisors is an integer number (106290907).

Almost surely, 2^212581813 is an apocalyptic number.

It is an amenable number.

212581813 is a deficient number, since it is larger than the sum of its proper divisors (1).

212581813 is an equidigital number, since it uses as much as digits as its factorization.

212581813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3840, while the sum is 31.

The square root of 212581813 is about 14580.1856298197. The cubic root of 212581813 is about 596.8181684438.

It can be divided in two parts, 2125 and 81813, that added together give a palindrome (83938).

The spelling of 212581813 in words is "two hundred twelve million, five hundred eighty-one thousand, eight hundred thirteen".