20406047 has 4 divisors (see below), whose sum is σ = 20442480. Its totient is φ = 20369616.

The previous prime is 20406017. The next prime is 20406107. The reversal of 20406047 is 74060402.

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 20406047 - 2¹² = 20401951 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 (20406017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17363 + ... + 18500.

It is an arithmetic number, because the mean of its divisors is an integer number (5110620).

Almost surely, 2^20406047 is an apocalyptic number.

20406047 is a deficient number, since it is larger than the sum of its proper divisors (36433).

20406047 is an equidigital number, since it uses as much as digits as its factorization.

20406047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36432.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 20406047 is about 4517.3052808062. The cubic root of 20406047 is about 273.2664369636.

Adding to 20406047 its reverse (74060402), we get a palindrome (94466449).

The spelling of 20406047 in words is "twenty million, four hundred six thousand, forty-seven".