538721 has 2 divisors, whose sum is σ = 538722. Its totient is φ = 538720.

The previous prime is 538711. The next prime is 538723. The reversal of 538721 is 127835.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 483025 + 55696 = 695^2 + 236^2 .

It is a cyclic number.

It is not a de Polignac number, because 538721 - 2¹⁴ = 522337 is a prime.

It is a super-3 number, since 3×538721³ = 469043336310538083, which contains 333 as substring.

Together with 538723, it forms a pair of twin primes.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 538721.

It is not a weakly prime, because it can be changed into another prime (538723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 269360 + 269361.

It is an arithmetic number, because the mean of its divisors is an integer number (269361).

2⁵³⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

538721 is a deficient number, since it is larger than the sum of its proper divisors (1).

538721 is an equidigital number, since it uses as much as digits as its factorization.

538721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 26.

The square root of 538721 is about 733.9761576509. The cubic root of 538721 is about 81.3681861885.

The spelling of 538721 in words is "five hundred thirty-eight thousand, seven hundred twenty-one".