856708007581 has 2 divisors, whose sum is σ = 856708007582. Its totient is φ = 856708007580.

The previous prime is 856708007539. The next prime is 856708007593. The reversal of 856708007581 is 185700807658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 830952572356 + 25755435225 = 911566^2 + 160485^2 .

It is a cyclic number.

It is not a de Polignac number, because 856708007581 - 2¹¹ = 856708005533 is a prime.

It is a super-2 number, since 2×856708007581² (a number of 25 digits) contains 22 as substring.

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 polite number, since it can be written as a sum of consecutive naturals, namely, 428354003790 + 428354003791.

It is an arithmetic number, because the mean of its divisors is an integer number (428354003791).

Almost surely, 2^856708007581 is an apocalyptic number.

It is an amenable number.

856708007581 is a deficient number, since it is larger than the sum of its proper divisors (1).

856708007581 is an equidigital number, since it uses as much as digits as its factorization.

856708007581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3763200, while the sum is 55.

The spelling of 856708007581 in words is "eight hundred fifty-six billion, seven hundred eight million, seven thousand, five hundred eighty-one".