20717047 has 4 divisors (see below), whose sum is σ = 22310680. Its totient is φ = 19123416.

The previous prime is 20717041. The next prime is 20717057. The reversal of 20717047 is 74071702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74071702 = 2 ⋅37035851.

It is not a de Polignac number, because 20717047 - 2⁷ = 20716919 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 (20717041) 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, 796797 + ... + 796822.

It is an arithmetic number, because the mean of its divisors is an integer number (5577670).

Almost surely, 2^20717047 is an apocalyptic number.

20717047 is a deficient number, since it is larger than the sum of its proper divisors (1593633).

20717047 is a wasteful number, since it uses less digits than its factorization.

20717047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593632.

The product of its (nonzero) digits is 2744, while the sum is 28.

The square root of 20717047 is about 4551.5982907106. The cubic root of 20717047 is about 274.6476898853.

Adding to 20717047 its reverse (74071702), we get a palindrome (94788749).

The spelling of 20717047 in words is "twenty million, seven hundred seventeen thousand, forty-seven".