20123013001991 has 2 divisors, whose sum is σ = 20123013001992. Its totient is φ = 20123013001990.

The previous prime is 20123013001979. The next prime is 20123013002087. The reversal of 20123013001991 is 19910031032102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20123013001991 - 2¹⁸ = 20123012739847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20123013001291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10061506500995 + 10061506500996.

It is an arithmetic number, because the mean of its divisors is an integer number (10061506500996).

Almost surely, 2^{20123013001991} is an apocalyptic number.

20123013001991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20123013001991 is an equidigital number, since it uses as much as digits as its factorization.

20123013001991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 32.

The spelling of 20123013001991 in words is "twenty trillion, one hundred twenty-three billion, thirteen million, one thousand, nine hundred ninety-one".