213635477681 has 2 divisors, whose sum is σ = 213635477682. Its totient is φ = 213635477680.

The previous prime is 213635477669. The next prime is 213635477683. The reversal of 213635477681 is 186774536312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 186443467681 + 27192010000 = 431791^2 + 164900^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213635477681 is a prime.

It is a super-2 number, since 2×213635477681² (a number of 23 digits) contains 22 as substring.

Together with 213635477683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (213635477683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106817738840 + 106817738841.

It is an arithmetic number, because the mean of its divisors is an integer number (106817738841).

Almost surely, 2^213635477681 is an apocalyptic number.

It is an amenable number.

213635477681 is a deficient number, since it is larger than the sum of its proper divisors (1).

213635477681 is an equidigital number, since it uses as much as digits as its factorization.

213635477681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5080320, while the sum is 53.

The spelling of 213635477681 in words is "two hundred thirteen billion, six hundred thirty-five million, four hundred seventy-seven thousand, six hundred eighty-one".