1640168879 has 4 divisors (see below), whose sum is σ = 1680173040. Its totient is φ = 1600164720.

The previous prime is 1640168869. The next prime is 1640168903. The reversal of 1640168879 is 9788610461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9788610461 = 7 ⋅1398372923.

It is a cyclic number.

It is not a de Polignac number, because 1640168879 - 2²⁰ = 1639120303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640168869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20002019 + ... + 20002100.

It is an arithmetic number, because the mean of its divisors is an integer number (420043260).

Almost surely, 2^1640168879 is an apocalyptic number.

1640168879 is a deficient number, since it is larger than the sum of its proper divisors (40004161).

1640168879 is an equidigital number, since it uses as much as digits as its factorization.

1640168879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40004160.

The product of its (nonzero) digits is 580608, while the sum is 50.

The square root of 1640168879 is about 40498.9984937899. The cubic root of 1640168879 is about 1179.3141851748.

The spelling of 1640168879 in words is "one billion, six hundred forty million, one hundred sixty-eight thousand, eight hundred seventy-nine".