647138693 has 2 divisors, whose sum is σ = 647138694. Its totient is φ = 647138692.

The previous prime is 647138623. The next prime is 647138707. The reversal of 647138693 is 396831746.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 345699649 + 301439044 = 18593^2 + 17362^2 .

It is a cyclic number.

It is not a de Polignac number, because 647138693 - 2¹⁴ = 647122309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647138623) 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, 323569346 + 323569347.

It is an arithmetic number, because the mean of its divisors is an integer number (323569347).

Almost surely, 2^647138693 is an apocalyptic number.

It is an amenable number.

647138693 is a deficient number, since it is larger than the sum of its proper divisors (1).

647138693 is an equidigital number, since it uses as much as digits as its factorization.

647138693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 47.

The square root of 647138693 is about 25438.9208300981. The cubic root of 647138693 is about 864.9661710628.

The spelling of 647138693 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, six hundred ninety-three".