212021209991 has 2 divisors, whose sum is σ = 212021209992. Its totient is φ = 212021209990.

The previous prime is 212021209987. The next prime is 212021210033. The reversal of 212021209991 is 199902120212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 212021209991 - 2² = 212021209987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212021209901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106010604995 + 106010604996.

It is an arithmetic number, because the mean of its divisors is an integer number (106010604996).

Almost surely, 2^212021209991 is an apocalyptic number.

212021209991 is a deficient number, since it is larger than the sum of its proper divisors (1).

212021209991 is an equidigital number, since it uses as much as digits as its factorization.

212021209991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 38.

The spelling of 212021209991 in words is "two hundred twelve billion, twenty-one million, two hundred nine thousand, nine hundred ninety-one".