513725821 has 4 divisors (see below), whose sum is σ = 587115232. Its totient is φ = 440336412.

The previous prime is 513725789. The next prime is 513725827. The reversal of 513725821 is 128527315.

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 513725821 - 2⁵ = 513725789 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 (513725827) 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, 36694695 + ... + 36694708.

It is an arithmetic number, because the mean of its divisors is an integer number (146778808).

Almost surely, 2^513725821 is an apocalyptic number.

It is an amenable number.

513725821 is a deficient number, since it is larger than the sum of its proper divisors (73389411).

513725821 is an equidigital number, since it uses as much as digits as its factorization.

513725821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73389410.

The product of its digits is 16800, while the sum is 34.

The square root of 513725821 is about 22665.5205322975. The cubic root of 513725821 is about 800.8978570431.

The spelling of 513725821 in words is "five hundred thirteen million, seven hundred twenty-five thousand, eight hundred twenty-one".