647921447 has 2 divisors, whose sum is σ = 647921448. Its totient is φ = 647921446.

The previous prime is 647921441. The next prime is 647921473. The reversal of 647921447 is 744129746.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647921447 - 2⁶ = 647921383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 647921398 and 647921407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647921441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323960723 + 323960724.

It is an arithmetic number, because the mean of its divisors is an integer number (323960724).

Almost surely, 2^647921447 is an apocalyptic number.

647921447 is a deficient number, since it is larger than the sum of its proper divisors (1).

647921447 is an equidigital number, since it uses as much as digits as its factorization.

647921447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 44.

The square root of 647921447 is about 25454.3011493146. The cubic root of 647921447 is about 865.3147737867.

The spelling of 647921447 in words is "six hundred forty-seven million, nine hundred twenty-one thousand, four hundred forty-seven".