212121999961 has 2 divisors, whose sum is σ = 212121999962. Its totient is φ = 212121999960.

The previous prime is 212121999913. The next prime is 212121999977. The reversal of 212121999961 is 169999121212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151841929561 + 60280070400 = 389669^2 + 245520^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121999961 - 2¹⁹ = 212121475673 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212121999899 and 212121999908.

It is not a weakly prime, because it can be changed into another prime (212121999461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106060999980 + 106060999981.

It is an arithmetic number, because the mean of its divisors is an integer number (106060999981).

Almost surely, 2^212121999961 is an apocalyptic number.

It is an amenable number.

212121999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

212121999961 is an equidigital number, since it uses as much as digits as its factorization.

212121999961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 52.

The spelling of 212121999961 in words is "two hundred twelve billion, one hundred twenty-one million, nine hundred ninety-nine thousand, nine hundred sixty-one".