20209447 has 8 divisors (see below), whose sum is σ = 21762000. Its totient is φ = 18697344.

The previous prime is 20209429. The next prime is 20209457. The reversal of 20209447 is 74490202.

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 20209447 - 2²³ = 11820839 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 (20209457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9072 + ... + 11077.

It is an arithmetic number, because the mean of its divisors is an integer number (2720250).

Almost surely, 2^20209447 is an apocalyptic number.

20209447 is a deficient number, since it is larger than the sum of its proper divisors (1552553).

20209447 is a wasteful number, since it uses less digits than its factorization.

20209447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20225.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 20209447 is about 4495.4918529567. The cubic root of 20209447 is about 272.3860174756.

Adding to 20209447 its reverse (74490202), we get a palindrome (94699649).

The spelling of 20209447 in words is "twenty million, two hundred nine thousand, four hundred forty-seven".