647249869 has 12 divisors (see below), whose sum is σ = 778887900. Its totient is φ = 535653888.

The previous prime is 647249861. The next prime is 647249879. The reversal of 647249869 is 968942746.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 244766025 + 402483844 = 15645^2 + 20062^2 .

It is not a de Polignac number, because 647249869 - 2³ = 647249861 is a prime.

It is a super-2 number, since 2×647249869² = 837864785841034322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647249861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 226324 + ... + 229165.

It is an arithmetic number, because the mean of its divisors is an integer number (64907325).

Almost surely, 2^647249869 is an apocalyptic number.

It is an amenable number.

647249869 is a deficient number, since it is larger than the sum of its proper divisors (131638031).

647249869 is a wasteful number, since it uses less digits than its factorization.

647249869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455532 (or 455525 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 55.

The square root of 647249869 is about 25441.1058918436. The cubic root of 647249869 is about 865.0157008744.

The spelling of 647249869 in words is "six hundred forty-seven million, two hundred forty-nine thousand, eight hundred sixty-nine".