855826421 has 2 divisors, whose sum is σ = 855826422. Its totient is φ = 855826420.

The previous prime is 855826399. The next prime is 855826423. The reversal of 855826421 is 124628558.

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., 834574321 + 21252100 = 28889^2 + 4610^2 .

It is a cyclic number.

It is not a de Polignac number, because 855826421 - 2²⁶ = 788717557 is a prime.

It is a Sophie Germain prime.

Together with 855826423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (855826423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427913210 + 427913211.

It is an arithmetic number, because the mean of its divisors is an integer number (427913211).

Almost surely, 2^855826421 is an apocalyptic number.

It is an amenable number.

855826421 is a deficient number, since it is larger than the sum of its proper divisors (1).

855826421 is an equidigital number, since it uses as much as digits as its factorization.

855826421 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 855826421 is about 29254.5111222184. The cubic root of 855826421 is about 949.4276962964.

The spelling of 855826421 in words is "eight hundred fifty-five million, eight hundred twenty-six thousand, four hundred twenty-one".