20571217 has 8 divisors (see below), whose sum is σ = 21198240. Its totient is φ = 19950240.

The previous prime is 20571209. The next prime is 20571247. The reversal of 20571217 is 71217502.

It is a happy number.

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 20571217 - 2³ = 20571209 is a prime.

It is a super-2 number, since 2×20571217² = 846349937722178, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20571191 and 20571200.

It is not an unprimeable number, because it can be changed into a prime (20571247) 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, 5938 + ... + 8740.

It is an arithmetic number, because the mean of its divisors is an integer number (2649780).

Almost surely, 2^20571217 is an apocalyptic number.

It is an amenable number.

20571217 is a deficient number, since it is larger than the sum of its proper divisors (627023).

20571217 is a wasteful number, since it uses less digits than its factorization.

20571217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3023.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 20571217 is about 4535.5503524931. The cubic root of 20571217 is about 274.0017448874.

Adding to 20571217 its reverse (71217502), we get a palindrome (91788719).

The spelling of 20571217 in words is "twenty million, five hundred seventy-one thousand, two hundred seventeen".