2856421 has 2 divisors, whose sum is σ = 2856422. Its totient is φ = 2856420.

The previous prime is 2856419. The next prime is 2856431. The reversal of 2856421 is 1246582.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1677025 + 1179396 = 1295^2 + 1086^2 .

It is a cyclic number.

It is not a de Polignac number, because 2856421 - 2¹ = 2856419 is a prime.

Together with 2856419, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2856421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2856431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1428210 + 1428211.

It is an arithmetic number, because the mean of its divisors is an integer number (1428211).

2^2856421 is an apocalyptic number.

It is an amenable number.

2856421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2856421 is an equidigital number, since it uses as much as digits as its factorization.

2856421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 28.

The square root of 2856421 is about 1690.0949677459. The cubic root of 2856421 is about 141.8863899852.

The spelling of 2856421 in words is "two million, eight hundred fifty-six thousand, four hundred twenty-one".