647538769 has 2 divisors, whose sum is σ = 647538770. Its totient is φ = 647538768.

The previous prime is 647538737. The next prime is 647538811. The reversal of 647538769 is 967835746.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641102400 + 6436369 = 25320^2 + 2537^2 .

It is a cyclic number.

It is not a de Polignac number, because 647538769 - 2⁵ = 647538737 is a prime.

It is a super-2 number, since 2×647538769² = 838612914716070722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (647538569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323769384 + 323769385.

It is an arithmetic number, because the mean of its divisors is an integer number (323769385).

Almost surely, 2^647538769 is an apocalyptic number.

It is an amenable number.

647538769 is a deficient number, since it is larger than the sum of its proper divisors (1).

647538769 is an equidigital number, since it uses as much as digits as its factorization.

647538769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7620480, while the sum is 55.

The square root of 647538769 is about 25446.7830776309. The cubic root of 647538769 is about 865.1443816595.

The spelling of 647538769 in words is "six hundred forty-seven million, five hundred thirty-eight thousand, seven hundred sixty-nine".