2628781 has 2 divisors, whose sum is σ = 2628782. Its totient is φ = 2628780.

The previous prime is 2628779. The next prime is 2628809. The reversal of 2628781 is 1878262.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2353156 + 275625 = 1534^2 + 525^2 .

It is a cyclic number.

It is not a de Polignac number, because 2628781 - 2¹ = 2628779 is a prime.

It is a super-2 number, since 2×2628781² = 13820979091922, which contains 22 as substring.

Together with 2628779, it forms a pair of twin primes.

It is equal to p₁₉₁₇₉₇ and since 2628781 and 191797 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2628481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1314390 + 1314391.

It is an arithmetic number, because the mean of its divisors is an integer number (1314391).

2^2628781 is an apocalyptic number.

It is an amenable number.

2628781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2628781 is an equidigital number, since it uses as much as digits as its factorization.

2628781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 2628781 is about 1621.3515966625. The cubic root of 2628781 is about 138.0124087421.

The spelling of 2628781 in words is "two million, six hundred twenty-eight thousand, seven hundred eighty-one".