516545821 has 4 divisors (see below), whose sum is σ = 563504544. Its totient is φ = 469587100.

The previous prime is 516545797. The next prime is 516545879. The reversal of 516545821 is 128545615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 516545821 - 2¹⁷ = 516414749 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 (516545881) 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, 23479345 + ... + 23479366.

It is an arithmetic number, because the mean of its divisors is an integer number (140876136).

Almost surely, 2^516545821 is an apocalyptic number.

It is an amenable number.

516545821 is a deficient number, since it is larger than the sum of its proper divisors (46958723).

516545821 is a wasteful number, since it uses less digits than its factorization.

516545821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46958722.

The product of its digits is 48000, while the sum is 37.

The square root of 516545821 is about 22727.6444225969. The cubic root of 516545821 is about 802.3606424616.

It can be divided in two parts, 51654 and 5821, that added together give a palindrome (57475).

The spelling of 516545821 in words is "five hundred sixteen million, five hundred forty-five thousand, eight hundred twenty-one".