517171021 has 4 divisors (see below), whose sum is σ = 517390972. Its totient is φ = 516951072.

The previous prime is 517171009. The next prime is 517171037. The reversal of 517171021 is 120171715.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 197262025 + 319908996 = 14045^2 + 17886^2 .

It is a cyclic number.

It is not a de Polignac number, because 517171021 - 2⁵ = 517170989 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 (517171121) 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, 106410 + ... + 111163.

It is an arithmetic number, because the mean of its divisors is an integer number (129347743).

Almost surely, 2^517171021 is an apocalyptic number.

It is an amenable number.

517171021 is a deficient number, since it is larger than the sum of its proper divisors (219951).

517171021 is a wasteful number, since it uses less digits than its factorization.

517171021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219950.

The product of its (nonzero) digits is 490, while the sum is 25.

The square root of 517171021 is about 22741.3944383364. The cubic root of 517171021 is about 802.6842237101.

The spelling of 517171021 in words is "five hundred seventeen million, one hundred seventy-one thousand, twenty-one".