647921441 has 2 divisors, whose sum is σ = 647921442. Its totient is φ = 647921440.

The previous prime is 647921437. The next prime is 647921447. The reversal of 647921441 is 144129746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 646176400 + 1745041 = 25420^2 + 1321^2 .

It is a cyclic number.

It is not a de Polignac number, because 647921441 - 2² = 647921437 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 647921395 and 647921404.

It is not a weakly prime, because it can be changed into another prime (647921447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323960720 + 323960721.

It is an arithmetic number, because the mean of its divisors is an integer number (323960721).

Almost surely, 2^647921441 is an apocalyptic number.

It is an amenable number.

647921441 is a deficient number, since it is larger than the sum of its proper divisors (1).

647921441 is an equidigital number, since it uses as much as digits as its factorization.

647921441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 38.

The square root of 647921441 is about 25454.3010314564. The cubic root of 647921441 is about 865.3147711156.

The spelling of 647921441 in words is "six hundred forty-seven million, nine hundred twenty-one thousand, four hundred forty-one".