783721 has 2 divisors, whose sum is σ = 783722. Its totient is φ = 783720.

The previous prime is 783719. The next prime is 783733. The reversal of 783721 is 127387.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 714025 + 69696 = 845^2 + 264^2 .

It is a cyclic number.

It is not a de Polignac number, because 783721 - 2¹ = 783719 is a prime.

It is a super-2 number, since 2×783721² = 1228437211682, which contains 22 as substring.

Together with 783719, it forms a pair of twin primes.

It is a Chen prime.

783721 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 783721.

It is not a weakly prime, because it can be changed into another prime (783701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 391860 + 391861.

It is an arithmetic number, because the mean of its divisors is an integer number (391861).

2⁷⁸³⁷²¹ is an apocalyptic number.

It is an amenable number.

783721 is a deficient number, since it is larger than the sum of its proper divisors (1).

783721 is an equidigital number, since it uses as much as digits as its factorization.

783721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2352, while the sum is 28.

The square root of 783721 is about 885.2801816374. The cubic root of 783721 is about 92.1977865185.

The spelling of 783721 in words is "seven hundred eighty-three thousand, seven hundred twenty-one".