1640782747 has 4 divisors (see below), whose sum is σ = 1640955136. Its totient is φ = 1640610360.

The previous prime is 1640782721. The next prime is 1640782751. The reversal of 1640782747 is 7472870461.

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 1640782747 - 2²⁷ = 1506565019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1640782697 and 1640782706.

It is not an unprimeable number, because it can be changed into a prime (1640782757) 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 3 ways as a sum of consecutive naturals, for example, 71028 + ... + 91249.

It is an arithmetic number, because the mean of its divisors is an integer number (410238784).

Almost surely, 2^1640782747 is an apocalyptic number.

1640782747 is a deficient number, since it is larger than the sum of its proper divisors (172389).

1640782747 is a wasteful number, since it uses less digits than its factorization.

1640782747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172388.

The product of its (nonzero) digits is 526848, while the sum is 46.

The square root of 1640782747 is about 40506.5765894873. The cubic root of 1640782747 is about 1179.4612946079.

The spelling of 1640782747 in words is "one billion, six hundred forty million, seven hundred eighty-two thousand, seven hundred forty-seven".