728381 has 2 divisors, whose sum is σ = 728382. Its totient is φ = 728380.

The previous prime is 728369. The next prime is 728383. The reversal of 728381 is 183827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511225 + 217156 = 715^2 + 466^2 .

It is a cyclic number.

It is not a de Polignac number, because 728381 - 2⁶ = 728317 is a prime.

It is a super-2 number, since 2×728381² = 1061077762322, which contains 22 as substring.

Together with 728383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 728381.

It is not a weakly prime, because it can be changed into another prime (728383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364190 + 364191.

It is an arithmetic number, because the mean of its divisors is an integer number (364191).

2⁷²⁸³⁸¹ is an apocalyptic number.

It is an amenable number.

728381 is a deficient number, since it is larger than the sum of its proper divisors (1).

728381 is an equidigital number, since it uses as much as digits as its factorization.

728381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 29.

The square root of 728381 is about 853.4524005473. The cubic root of 728381 is about 89.9745195357.

The spelling of 728381 in words is "seven hundred twenty-eight thousand, three hundred eighty-one".