20105212091 has 2 divisors, whose sum is σ = 20105212092. Its totient is φ = 20105212090.

The previous prime is 20105212081. The next prime is 20105212097. The reversal of 20105212091 is 19021250102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20105212091 - 2¹⁰ = 20105211067 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20105212097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10052606045 + 10052606046.

It is an arithmetic number, because the mean of its divisors is an integer number (10052606046).

Almost surely, 2^20105212091 is an apocalyptic number.

20105212091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20105212091 is an equidigital number, since it uses as much as digits as its factorization.

20105212091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 23.

Adding to 20105212091 its reverse (19021250102), we get a palindrome (39126462193).

The spelling of 20105212091 in words is "twenty billion, one hundred five million, two hundred twelve thousand, ninety-one".