20390447 has 8 divisors (see below), whose sum is σ = 25421952. Its totient is φ = 15888600.

The previous prime is 20390431. The next prime is 20390483. The reversal of 20390447 is 74409302.

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

It is not a de Polignac number, because 20390447 - 2⁴ = 20390431 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 (20390047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132329 + ... + 132482.

It is an arithmetic number, because the mean of its divisors is an integer number (3177744).

Almost surely, 2^20390447 is an apocalyptic number.

20390447 is a deficient number, since it is larger than the sum of its proper divisors (5031505).

20390447 is a wasteful number, since it uses less digits than its factorization.

20390447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264829.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 20390447 is about 4515.5782575435. The cubic root of 20390447 is about 273.1967837019.

Adding to 20390447 its reverse (74409302), we get a palindrome (94799749).

The spelling of 20390447 in words is "twenty million, three hundred ninety thousand, four hundred forty-seven".