20091023 has 2 divisors, whose sum is σ = 20091024. Its totient is φ = 20091022.

The previous prime is 20090977. The next prime is 20091053. The reversal of 20091023 is 32019002.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20091023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20090992 and 20091010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20091053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10045511 + 10045512.

It is an arithmetic number, because the mean of its divisors is an integer number (10045512).

Almost surely, 2^20091023 is an apocalyptic number.

20091023 is a deficient number, since it is larger than the sum of its proper divisors (1).

20091023 is an equidigital number, since it uses as much as digits as its factorization.

20091023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20091023 is about 4482.3010831491. The cubic root of 20091023 is about 271.8529292516.

The spelling of 20091023 in words is "twenty million, ninety-one thousand, twenty-three".