6620401 has 2 divisors, whose sum is σ = 6620402. Its totient is φ = 6620400.

The previous prime is 6620399. The next prime is 6620407. The reversal of 6620401 is 1040266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3996001 + 2624400 = 1999^2 + 1620^2 .

It is a cyclic number.

It is not a de Polignac number, because 6620401 - 2¹ = 6620399 is a prime.

Together with 6620399, it forms a pair of twin primes.

6620401 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (6620407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3310200 + 3310201.

It is an arithmetic number, because the mean of its divisors is an integer number (3310201).

Almost surely, 2^6620401 is an apocalyptic number.

It is an amenable number.

6620401 is a deficient number, since it is larger than the sum of its proper divisors (1).

6620401 is an equidigital number, since it uses as much as digits as its factorization.

6620401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 6620401 is about 2573.0139914116. The cubic root of 6620401 is about 187.7708181334.

Adding to 6620401 its reverse (1040266), we get a palindrome (7660667).

It can be divided in two parts, 6620 and 401, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 6620401 in words is "six million, six hundred twenty thousand, four hundred one".