856708007621 has 2 divisors, whose sum is σ = 856708007622. Its totient is φ = 856708007620.

The previous prime is 856708007593. The next prime is 856708007633. The reversal of 856708007621 is 126700807658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 744958872100 + 111749135521 = 863110^2 + 334289^2 .

It is a cyclic number.

It is not a de Polignac number, because 856708007621 - 2¹⁸ = 856707745477 is a prime.

It is a super-2 number, since 2×856708007621² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 856708007621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856708007521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428354003810 + 428354003811.

It is an arithmetic number, because the mean of its divisors is an integer number (428354003811).

Almost surely, 2^856708007621 is an apocalyptic number.

It is an amenable number.

856708007621 is a deficient number, since it is larger than the sum of its proper divisors (1).

856708007621 is an equidigital number, since it uses as much as digits as its factorization.

856708007621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1128960, while the sum is 50.

The spelling of 856708007621 in words is "eight hundred fifty-six billion, seven hundred eight million, seven thousand, six hundred twenty-one".