20517671 has 4 divisors (see below), whose sum is σ = 21018144. Its totient is φ = 20017200.

The previous prime is 20517661. The next prime is 20517677. The reversal of 20517671 is 17671502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17671502 = 2 ⋅8835751.

It is a cyclic number.

It is not a de Polignac number, because 20517671 - 2¹⁴ = 20501287 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 (20517677) 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, 250175 + ... + 250256.

It is an arithmetic number, because the mean of its divisors is an integer number (5254536).

Almost surely, 2^20517671 is an apocalyptic number.

20517671 is a deficient number, since it is larger than the sum of its proper divisors (500473).

20517671 is an equidigital number, since it uses as much as digits as its factorization.

20517671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500472.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 20517671 is about 4529.6435842128. The cubic root of 20517671 is about 273.7638000313.

The spelling of 20517671 in words is "twenty million, five hundred seventeen thousand, six hundred seventy-one".