2780621 has 2 divisors, whose sum is σ = 2780622. Its totient is φ = 2780620.

The previous prime is 2780599. The next prime is 2780623. The reversal of 2780621 is 1260872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2515396 + 265225 = 1586^2 + 515^2 .

It is a cyclic number.

It is not a de Polignac number, because 2780621 - 2¹⁰ = 2779597 is a prime.

Together with 2780623, 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 (2780623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1390310 + 1390311.

It is an arithmetic number, because the mean of its divisors is an integer number (1390311).

2^2780621 is an apocalyptic number.

It is an amenable number.

2780621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2780621 is an equidigital number, since it uses as much as digits as its factorization.

2780621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 2780621 is about 1667.5194151793. The cubic root of 2780621 is about 140.6200558591.

The spelling of 2780621 in words is "two million, seven hundred eighty thousand, six hundred twenty-one".