6620399 has 2 divisors, whose sum is σ = 6620400. Its totient is φ = 6620398.

The previous prime is 6620387. The next prime is 6620401. The reversal of 6620399 is 9930266.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6620399 is a prime.

Together with 6620401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6620309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3310199 + 3310200.

It is an arithmetic number, because the mean of its divisors is an integer number (3310200).

Almost surely, 2^6620399 is an apocalyptic number.

6620399 is a deficient number, since it is larger than the sum of its proper divisors (1).

6620399 is an equidigital number, since it uses as much as digits as its factorization.

6620399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 35.

The square root of 6620399 is about 2573.0136027623. The cubic root of 6620399 is about 187.7707992251.

The spelling of 6620399 in words is "six million, six hundred twenty thousand, three hundred ninety-nine".