213488889565781 has 2 divisors, whose sum is σ = 213488889565782. Its totient is φ = 213488889565780.

The previous prime is 213488889565747. The next prime is 213488889565799. The reversal of 213488889565781 is 187565988884312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195967549343281 + 17521340222500 = 13998841^2 + 4185850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213488889565781 is a prime.

It is a super-2 number, since 2×213488889565781² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 213488889565781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213488889505781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106744444782890 + 106744444782891.

It is an arithmetic number, because the mean of its divisors is an integer number (106744444782891).

Almost surely, 2^{213488889565781} is an apocalyptic number.

It is an amenable number.

213488889565781 is a deficient number, since it is larger than the sum of its proper divisors (1).

213488889565781 is an equidigital number, since it uses as much as digits as its factorization.

213488889565781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7431782400, while the sum is 83.

The spelling of 213488889565781 in words is "two hundred thirteen trillion, four hundred eighty-eight billion, eight hundred eighty-nine million, five hundred sixty-five thousand, seven hundred eighty-one".