1647791649 has 27 divisors (see below), whose sum is σ = 2770171443. Its totient is φ = 941108112.

The previous prime is 1647791627. The next prime is 1647791683. The reversal of 1647791649 is 9461977461.

The square root of 1647791649 is 40593.

It is a perfect power (a square), and thus also a powerful number.

1647791649 is a `hidden beast` number, since 1 + 6 + 477 + 9 + 164 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1121915025 + 525876624 = 33495^2 + 22932^2 .

It is not a de Polignac number, because 1647791649 - 2²⁵ = 1614237217 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1647791595 and 1647791604.

It is not an unprimeable number, because it can be changed into a prime (1647791689) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 851487 + ... + 853419.

Almost surely, 2^1647791649 is an apocalyptic number.

1647791649 is the 40593-rd square number.

1647791649 is the 20297-th centered octagonal number.

It is an amenable number.

1647791649 is a deficient number, since it is larger than the sum of its proper divisors (1122379794).

1647791649 is an frugal number, since it uses more digits than its factorization.

1647791649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3886 (or 1943 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The cubic root of 1647791649 is about 1181.1383367699.

The spelling of 1647791649 in words is "one billion, six hundred forty-seven million, seven hundred ninety-one thousand, six hundred forty-nine".