2687821 has 2 divisors, whose sum is σ = 2687822. Its totient is φ = 2687820.

The previous prime is 2687813. The next prime is 2687827. The reversal of 2687821 is 1287862.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2340900 + 346921 = 1530^2 + 589^2 .

It is a cyclic number.

It is not a de Polignac number, because 2687821 - 2³ = 2687813 is a prime.

It is a nialpdrome in base 12.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2687827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1343910 + 1343911.

It is an arithmetic number, because the mean of its divisors is an integer number (1343911).

2^2687821 is an apocalyptic number.

It is an amenable number.

2687821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2687821 is an equidigital number, since it uses as much as digits as its factorization.

2687821 is an odious number, because the sum of its binary digits is odd.

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

The square root of 2687821 is about 1639.4575322344. The cubic root of 2687821 is about 139.0379793739.

The spelling of 2687821 in words is "two million, six hundred eighty-seven thousand, eight hundred twenty-one".