212005281991 has 2 divisors, whose sum is σ = 212005281992. Its totient is φ = 212005281990.

The previous prime is 212005281973. The next prime is 212005282051. The reversal of 212005281991 is 199182500212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 212005281991 - 2¹¹ = 212005279943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212005281941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106002640995 + 106002640996.

It is an arithmetic number, because the mean of its divisors is an integer number (106002640996).

Almost surely, 2^212005281991 is an apocalyptic number.

212005281991 is a deficient number, since it is larger than the sum of its proper divisors (1).

212005281991 is an equidigital number, since it uses as much as digits as its factorization.

212005281991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 40.

The spelling of 212005281991 in words is "two hundred twelve billion, five million, two hundred eighty-one thousand, nine hundred ninety-one".