6856621 has 2 divisors, whose sum is σ = 6856622. Its totient is φ = 6856620.

The previous prime is 6856613. The next prime is 6856631. The reversal of 6856621 is 1266586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6812100 + 44521 = 2610^2 + 211^2 .

It is a cyclic number.

It is not a de Polignac number, because 6856621 - 2³ = 6856613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6856601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3428310 + 3428311.

It is an arithmetic number, because the mean of its divisors is an integer number (3428311).

Almost surely, 2^6856621 is an apocalyptic number.

It is an amenable number.

6856621 is a deficient number, since it is larger than the sum of its proper divisors (1).

6856621 is an equidigital number, since it uses as much as digits as its factorization.

6856621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 34.

The square root of 6856621 is about 2618.5150371919. The cubic root of 6856621 is about 189.9780307008.

The spelling of 6856621 in words is "six million, eight hundred fifty-six thousand, six hundred twenty-one".