1668783647 has 4 divisors (see below), whose sum is σ = 1668910920. Its totient is φ = 1668656376.

The previous prime is 1668783643. The next prime is 1668783659. The reversal of 1668783647 is 7463878661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1668783647 - 2² = 1668783643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1668783592 and 1668783601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668783643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41372 + ... + 71057.

It is an arithmetic number, because the mean of its divisors is an integer number (417227730).

Almost surely, 2^1668783647 is an apocalyptic number.

1668783647 is a deficient number, since it is larger than the sum of its proper divisors (127273).

1668783647 is a wasteful number, since it uses less digits than its factorization.

1668783647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127272.

The product of its digits is 8128512, while the sum is 56.

The square root of 1668783647 is about 40850.7484264364. The cubic root of 1668783647 is about 1186.1328806502.

The spelling of 1668783647 in words is "one billion, six hundred sixty-eight million, seven hundred eighty-three thousand, six hundred forty-seven".