647663993 has 2 divisors, whose sum is σ = 647663994. Its totient is φ = 647663992.

The previous prime is 647663987. The next prime is 647663999. The reversal of 647663993 is 399366746.

647663993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (647663987) and next prime (647663999).

It can be written as a sum of positive squares in only one way, i.e., 612463504 + 35200489 = 24748^2 + 5933^2 .

It is a cyclic number.

It is not a de Polignac number, because 647663993 - 2¹⁰ = 647662969 is a prime.

It is not a weakly prime, because it can be changed into another prime (647663999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323831996 + 323831997.

It is an arithmetic number, because the mean of its divisors is an integer number (323831997).

Almost surely, 2^647663993 is an apocalyptic number.

It is an amenable number.

647663993 is a deficient number, since it is larger than the sum of its proper divisors (1).

647663993 is an equidigital number, since it uses as much as digits as its factorization.

647663993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4408992, while the sum is 53.

The square root of 647663993 is about 25449.2434661622. The cubic root of 647663993 is about 865.2001465868.

The spelling of 647663993 in words is "six hundred forty-seven million, six hundred sixty-three thousand, nine hundred ninety-three".