20989523 has 2 divisors, whose sum is σ = 20989524. Its totient is φ = 20989522.

The previous prime is 20989519. The next prime is 20989531. The reversal of 20989523 is 32598902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20989523 - 2² = 20989519 is a prime.

It is not a weakly prime, because it can be changed into another prime (20989513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10494761 + 10494762.

It is an arithmetic number, because the mean of its divisors is an integer number (10494762).

Almost surely, 2^20989523 is an apocalyptic number.

20989523 is a deficient number, since it is larger than the sum of its proper divisors (1).

20989523 is an equidigital number, since it uses as much as digits as its factorization.

20989523 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 20989523 is about 4581.4324179235. The cubic root of 20989523 is about 275.8465286589.

It can be divided in two parts, 20989 and 523, that added together give a palindrome (21512).

The spelling of 20989523 in words is "twenty million, nine hundred eighty-nine thousand, five hundred twenty-three".