821256713 has 8 divisors (see below), whose sum is σ = 850079880. Its totient is φ = 792467200.

The previous prime is 821256701. The next prime is 821256719. The reversal of 821256713 is 317652128.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 136492489 + 684764224 = 11683^2 + 26168^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 821256713 - 2⁶ = 821256649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821256719) 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 in 7 ways as a sum of consecutive naturals, for example, 47681 + ... + 62577.

It is an arithmetic number, because the mean of its divisors is an integer number (106259985).

Almost surely, 2^821256713 is an apocalyptic number.

It is an amenable number.

821256713 is a deficient number, since it is larger than the sum of its proper divisors (28823167).

821256713 is a wasteful number, since it uses less digits than its factorization.

821256713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16827.

The product of its digits is 20160, while the sum is 35.

The square root of 821256713 is about 28657.5768864013. The cubic root of 821256713 is about 936.4680771952.

The spelling of 821256713 in words is "eight hundred twenty-one million, two hundred fifty-six thousand, seven hundred thirteen".