2643961 has 2 divisors, whose sum is σ = 2643962. Its totient is φ = 2643960.

The previous prime is 2643947. The next prime is 2643989. The reversal of 2643961 is 1693462.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2499561 + 144400 = 1581^2 + 380^2 .

It is a cyclic number.

It is not a de Polignac number, because 2643961 - 2⁷ = 2643833 is a prime.

It is a d-powerful number, because it can be written as 2¹⁹ + 6² + 4⁹ + 3¹¹ + 9³ + 6⁸ + 1 .

It is not a weakly prime, because it can be changed into another prime (2643061) 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, 1321980 + 1321981.

It is an arithmetic number, because the mean of its divisors is an integer number (1321981).

2^2643961 is an apocalyptic number.

It is an amenable number.

2643961 is a deficient number, since it is larger than the sum of its proper divisors (1).

2643961 is an equidigital number, since it uses as much as digits as its factorization.

2643961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 31.

The square root of 2643961 is about 1626.0261375513. The cubic root of 2643961 is about 138.2775517423.

It can be divided in two parts, 264 and 3961, that added together give a square (4225 = 65²).

The spelling of 2643961 in words is "two million, six hundred forty-three thousand, nine hundred sixty-one".