856254821 has 2 divisors, whose sum is σ = 856254822. Its totient is φ = 856254820.

The previous prime is 856254781. The next prime is 856254853. The reversal of 856254821 is 128452658.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 498628900 + 357625921 = 22330^2 + 18911^2 .

It is a cyclic number.

It is not a de Polignac number, because 856254821 - 2²⁶ = 789145957 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856254881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428127410 + 428127411.

It is an arithmetic number, because the mean of its divisors is an integer number (428127411).

Almost surely, 2^856254821 is an apocalyptic number.

It is an amenable number.

856254821 is a deficient number, since it is larger than the sum of its proper divisors (1).

856254821 is an equidigital number, since it uses as much as digits as its factorization.

856254821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 153600, while the sum is 41.

The square root of 856254821 is about 29261.8321538485. The cubic root of 856254821 is about 949.5860878299.

The spelling of 856254821 in words is "eight hundred fifty-six million, two hundred fifty-four thousand, eight hundred twenty-one".