213021031709 has 2 divisors, whose sum is σ = 213021031710. Its totient is φ = 213021031708.

The previous prime is 213021031687. The next prime is 213021031733. The reversal of 213021031709 is 907130120312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212385487609 + 635544100 = 460853^2 + 25210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213021031709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213021031309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106510515854 + 106510515855.

It is an arithmetic number, because the mean of its divisors is an integer number (106510515855).

Almost surely, 2^213021031709 is an apocalyptic number.

It is an amenable number.

213021031709 is a deficient number, since it is larger than the sum of its proper divisors (1).

213021031709 is an equidigital number, since it uses as much as digits as its factorization.

213021031709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

The spelling of 213021031709 in words is "two hundred thirteen billion, twenty-one million, thirty-one thousand, seven hundred nine".