513535721 has 2 divisors, whose sum is σ = 513535722. Its totient is φ = 513535720.

The previous prime is 513535717. The next prime is 513535723. The reversal of 513535721 is 127535315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 505350400 + 8185321 = 22480^2 + 2861^2 .

It is a cyclic number.

It is not a de Polignac number, because 513535721 - 2² = 513535717 is a prime.

Together with 513535723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (513535723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 256767860 + 256767861.

It is an arithmetic number, because the mean of its divisors is an integer number (256767861).

Almost surely, 2^513535721 is an apocalyptic number.

It is an amenable number.

513535721 is a deficient number, since it is larger than the sum of its proper divisors (1).

513535721 is an equidigital number, since it uses as much as digits as its factorization.

513535721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15750, while the sum is 32.

The square root of 513535721 is about 22661.3265498735. The cubic root of 513535721 is about 800.7990563080.

The spelling of 513535721 in words is "five hundred thirteen million, five hundred thirty-five thousand, seven hundred twenty-one".