1648781 has 2 divisors, whose sum is σ = 1648782. Its totient is φ = 1648780.

The previous prime is 1648771. The next prime is 1648789. The reversal of 1648781 is 1878461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1522756 + 126025 = 1234^2 + 355^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1648781 is a prime.

It is a super-2 number, since 2×1648781² = 5436957571922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1648789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 824390 + 824391.

It is an arithmetic number, because the mean of its divisors is an integer number (824391).

2^1648781 is an apocalyptic number.

It is an amenable number.

1648781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1648781 is an equidigital number, since it uses as much as digits as its factorization.

1648781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 35.

The square root of 1648781 is about 1284.0486750899. The cubic root of 1648781 is about 118.1374678665.

The spelling of 1648781 in words is "one million, six hundred forty-eight thousand, seven hundred eighty-one".