647811397 has 2 divisors, whose sum is σ = 647811398. Its totient is φ = 647811396.

The previous prime is 647811349. The next prime is 647811407. The reversal of 647811397 is 793118746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 647498916 + 312481 = 25446^2 + 559^2 .

It is a cyclic number.

It is not a de Polignac number, because 647811397 - 2¹⁵ = 647778629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647811337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323905698 + 323905699.

It is an arithmetic number, because the mean of its divisors is an integer number (323905699).

Almost surely, 2^647811397 is an apocalyptic number.

It is an amenable number.

647811397 is a deficient number, since it is larger than the sum of its proper divisors (1).

647811397 is an equidigital number, since it uses as much as digits as its factorization.

647811397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 647811397 is about 25452.1393403384. The cubic root of 647811397 is about 865.2657795332.

The spelling of 647811397 in words is "six hundred forty-seven million, eight hundred eleven thousand, three hundred ninety-seven".