20389947 has 4 divisors (see below), whose sum is σ = 27186600. Its totient is φ = 13593296.

The previous prime is 20389927. The next prime is 20389951. The reversal of 20389947 is 74998302.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20389947 - 2⁶ = 20389883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20389899 and 20389908.

It is not an unprimeable number, because it can be changed into a prime (20389927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3398322 + ... + 3398327.

It is an arithmetic number, because the mean of its divisors is an integer number (6796650).

Almost surely, 2^20389947 is an apocalyptic number.

20389947 is a deficient number, since it is larger than the sum of its proper divisors (6796653).

20389947 is an equidigital number, since it uses as much as digits as its factorization.

20389947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6796652.

The product of its (nonzero) digits is 108864, while the sum is 42.

The square root of 20389947 is about 4515.5228933093. The cubic root of 20389947 is about 273.1945506381.

The spelling of 20389947 in words is "twenty million, three hundred eighty-nine thousand, nine hundred forty-seven".