20989505 has 8 divisors (see below), whose sum is σ = 25223400. Its totient is φ = 16767616.

The previous prime is 20989483. The next prime is 20989513. The reversal of 20989505 is 50598902.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8549776 + 12439729 = 2924^2 + 3527^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20989505 - 2¹⁰ = 20988481 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1451 + ... + 6639.

It is an arithmetic number, because the mean of its divisors is an integer number (3152925).

Almost surely, 2^20989505 is an apocalyptic number.

It is an amenable number.

20989505 is a deficient number, since it is larger than the sum of its proper divisors (4233895).

20989505 is an equidigital number, since it uses as much as digits as its factorization.

20989505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6003.

The product of its (nonzero) digits is 32400, while the sum is 38.

The square root of 20989505 is about 4581.4304534719. The cubic root of 20989505 is about 275.8464498062.

The spelling of 20989505 in words is "twenty million, nine hundred eighty-nine thousand, five hundred five".