829687721 has 2 divisors, whose sum is σ = 829687722. Its totient is φ = 829687720.

The previous prime is 829687699. The next prime is 829687739. The reversal of 829687721 is 127786928.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 593604496 + 236083225 = 24364^2 + 15365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-829687721 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 829687721.

It is not a weakly prime, because it can be changed into another prime (829587721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 414843860 + 414843861.

It is an arithmetic number, because the mean of its divisors is an integer number (414843861).

Almost surely, 2^829687721 is an apocalyptic number.

It is an amenable number.

829687721 is a deficient number, since it is larger than the sum of its proper divisors (1).

829687721 is an equidigital number, since it uses as much as digits as its factorization.

829687721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 677376, while the sum is 50.

The square root of 829687721 is about 28804.3003907403. The cubic root of 829687721 is about 939.6617618894.

The spelling of 829687721 in words is "eight hundred twenty-nine million, six hundred eighty-seven thousand, seven hundred twenty-one".