6621281 has 2 divisors, whose sum is σ = 6621282. Its totient is φ = 6621280.

The previous prime is 6621239. The next prime is 6621283. The reversal of 6621281 is 1821266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4661281 + 1960000 = 2159^2 + 1400^2 .

It is a cyclic number.

It is not a de Polignac number, because 6621281 - 2¹⁸ = 6359137 is a prime.

It is a super-2 number, since 2×6621281² = 87682724161922, which contains 22 as substring.

Together with 6621283, 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 6621281.

It is not a weakly prime, because it can be changed into another prime (6621283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3310640 + 3310641.

It is an arithmetic number, because the mean of its divisors is an integer number (3310641).

Almost surely, 2^6621281 is an apocalyptic number.

It is an amenable number.

6621281 is a deficient number, since it is larger than the sum of its proper divisors (1).

6621281 is an equidigital number, since it uses as much as digits as its factorization.

6621281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The square root of 6621281 is about 2573.1849914066. The cubic root of 6621281 is about 187.7791374179.

The spelling of 6621281 in words is "six million, six hundred twenty-one thousand, two hundred eighty-one".