647172769 has 2 divisors, whose sum is σ = 647172770. Its totient is φ = 647172768.

The previous prime is 647172763. The next prime is 647172821. The reversal of 647172769 is 967271746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 524959744 + 122213025 = 22912^2 + 11055^2 .

It is a cyclic number.

It is not a de Polignac number, because 647172769 - 2³ = 647172761 is a prime.

It is a super-2 number, since 2×647172769² = 837665185870254722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (647172761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323586384 + 323586385.

It is an arithmetic number, because the mean of its divisors is an integer number (323586385).

Almost surely, 2^647172769 is an apocalyptic number.

It is an amenable number.

647172769 is a deficient number, since it is larger than the sum of its proper divisors (1).

647172769 is an equidigital number, since it uses as much as digits as its factorization.

647172769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 889056, while the sum is 49.

The square root of 647172769 is about 25439.5905823974. The cubic root of 647172769 is about 864.9813528006.

The spelling of 647172769 in words is "six hundred forty-seven million, one hundred seventy-two thousand, seven hundred sixty-nine".