6856815025397 has 2 divisors, whose sum is σ = 6856815025398. Its totient is φ = 6856815025396.

The previous prime is 6856815025367. The next prime is 6856815025447. The reversal of 6856815025397 is 7935205186586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6054704918161 + 802110107236 = 2460631^2 + 895606^2 .

It is a cyclic number.

It is not a de Polignac number, because 6856815025397 - 2⁸ = 6856815025141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6856815025367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3428407512698 + 3428407512699.

It is an arithmetic number, because the mean of its divisors is an integer number (3428407512699).

Almost surely, 2^{6856815025397} is an apocalyptic number.

It is an amenable number.

6856815025397 is a deficient number, since it is larger than the sum of its proper divisors (1).

6856815025397 is an equidigital number, since it uses as much as digits as its factorization.

6856815025397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864000, while the sum is 65.

The spelling of 6856815025397 in words is "six trillion, eight hundred fifty-six billion, eight hundred fifteen million, twenty-five thousand, three hundred ninety-seven".