212021121709 has 2 divisors, whose sum is σ = 212021121710. Its totient is φ = 212021121708.

The previous prime is 212021121661. The next prime is 212021121737. The reversal of 212021121709 is 907121120212.

It is an a-pointer prime, because the next prime (212021121737) can be obtained adding 212021121709 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129976112484 + 82045009225 = 360522^2 + 286435^2 .

It is a cyclic number.

It is not a de Polignac number, because 212021121709 - 2¹³ = 212021113517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212021121749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106010560854 + 106010560855.

It is an arithmetic number, because the mean of its divisors is an integer number (106010560855).

Almost surely, 2^212021121709 is an apocalyptic number.

It is an amenable number.

212021121709 is a deficient number, since it is larger than the sum of its proper divisors (1).

212021121709 is an equidigital number, since it uses as much as digits as its factorization.

212021121709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 28.

The spelling of 212021121709 in words is "two hundred twelve billion, twenty-one million, one hundred twenty-one thousand, seven hundred nine".