213121121309 has 2 divisors, whose sum is σ = 213121121310. Its totient is φ = 213121121308.

The previous prime is 213121121281. The next prime is 213121121341. The reversal of 213121121309 is 903121121312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187450032025 + 25671089284 = 432955^2 + 160222^2 .

It is a cyclic number.

It is not a de Polignac number, because 213121121309 - 2⁸ = 213121121053 is a prime.

It is a super-2 number, since 2×213121121309² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213121124309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106560560654 + 106560560655.

It is an arithmetic number, because the mean of its divisors is an integer number (106560560655).

Almost surely, 2^213121121309 is an apocalyptic number.

It is an amenable number.

213121121309 is a deficient number, since it is larger than the sum of its proper divisors (1).

213121121309 is an equidigital number, since it uses as much as digits as its factorization.

213121121309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 26.

The spelling of 213121121309 in words is "two hundred thirteen billion, one hundred twenty-one million, one hundred twenty-one thousand, three hundred nine".