856538406523 has 2 divisors, whose sum is σ = 856538406524. Its totient is φ = 856538406522.

The previous prime is 856538406467. The next prime is 856538406541. The reversal of 856538406523 is 325604835658.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 856538406523 - 2²⁹ = 856001535611 is a prime.

It is not a weakly prime, because it can be changed into another prime (856538404523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428269203261 + 428269203262.

It is an arithmetic number, because the mean of its divisors is an integer number (428269203262).

Almost surely, 2^856538406523 is an apocalyptic number.

856538406523 is a deficient number, since it is larger than the sum of its proper divisors (1).

856538406523 is an equidigital number, since it uses as much as digits as its factorization.

856538406523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736000, while the sum is 55.

The spelling of 856538406523 in words is "eight hundred fifty-six billion, five hundred thirty-eight million, four hundred six thousand, five hundred twenty-three".