20989839 has 8 divisors (see below), whose sum is σ = 30139312. Its totient is φ = 12916800.

The previous prime is 20989807. The next prime is 20989847. The reversal of 20989839 is 93898902.

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

It is not a de Polignac number, because 20989839 - 2⁵ = 20989807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989879) 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 in 7 ways as a sum of consecutive naturals, for example, 269062 + ... + 269139.

It is an arithmetic number, because the mean of its divisors is an integer number (3767414).

Almost surely, 2^20989839 is an apocalyptic number.

20989839 is a deficient number, since it is larger than the sum of its proper divisors (9149473).

20989839 is a wasteful number, since it uses less digits than its factorization.

20989839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538217.

The product of its (nonzero) digits is 279936, while the sum is 48.

The square root of 20989839 is about 4581.4669048243. The cubic root of 20989839 is about 275.8479129537.

The spelling of 20989839 in words is "twenty million, nine hundred eighty-nine thousand, eight hundred thirty-nine".