20323021991 has 2 divisors, whose sum is σ = 20323021992. Its totient is φ = 20323021990.

The previous prime is 20323021921. The next prime is 20323022039. The reversal of 20323021991 is 19912032302.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20323021991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20323021921) 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, 10161510995 + 10161510996.

It is an arithmetic number, because the mean of its divisors is an integer number (10161510996).

Almost surely, 2^20323021991 is an apocalyptic number.

20323021991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20323021991 is an equidigital number, since it uses as much as digits as its factorization.

20323021991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 32.

The spelling of 20323021991 in words is "twenty billion, three hundred twenty-three million, twenty-one thousand, nine hundred ninety-one".