6420881 has 2 divisors, whose sum is σ = 6420882. Its totient is φ = 6420880.

The previous prime is 6420877. The next prime is 6420893. The reversal of 6420881 is 1880246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5958481 + 462400 = 2441^2 + 680^2 .

It is a cyclic number.

It is not a de Polignac number, because 6420881 - 2² = 6420877 is a prime.

It is a super-2 number, since 2×6420881² = 82455425632322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6420851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3210440 + 3210441.

It is an arithmetic number, because the mean of its divisors is an integer number (3210441).

Almost surely, 2^6420881 is an apocalyptic number.

It is an amenable number.

6420881 is a deficient number, since it is larger than the sum of its proper divisors (1).

6420881 is an equidigital number, since it uses as much as digits as its factorization.

6420881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 6420881 is about 2533.9457373827. The cubic root of 6420881 is about 185.8652529287.

The spelling of 6420881 in words is "six million, four hundred twenty thousand, eight hundred eighty-one".