20101210219991 has 2 divisors, whose sum is σ = 20101210219992. Its totient is φ = 20101210219990.

The previous prime is 20101210219969. The next prime is 20101210220093. The reversal of 20101210219991 is 19991201210102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20101210219991 - 2²² = 20101206025687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20101210219291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050605109995 + 10050605109996.

It is an arithmetic number, because the mean of its divisors is an integer number (10050605109996).

Almost surely, 2^{20101210219991} is an apocalyptic number.

20101210219991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101210219991 is an equidigital number, since it uses as much as digits as its factorization.

20101210219991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 38.

The spelling of 20101210219991 in words is "twenty trillion, one hundred one billion, two hundred ten million, two hundred nineteen thousand, nine hundred ninety-one".