1640712779 has 2 divisors, whose sum is σ = 1640712780. Its totient is φ = 1640712778.

The previous prime is 1640712767. The next prime is 1640712803. The reversal of 1640712779 is 9772170461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1640712779 - 2²⁸ = 1372277323 is a prime.

It is not a weakly prime, because it can be changed into another prime (1640712079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820356389 + 820356390.

It is an arithmetic number, because the mean of its divisors is an integer number (820356390).

Almost surely, 2^1640712779 is an apocalyptic number.

1640712779 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640712779 is an equidigital number, since it uses as much as digits as its factorization.

1640712779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 148176, while the sum is 44.

The square root of 1640712779 is about 40505.7129180564. The cubic root of 1640712779 is about 1179.4445290893. Note that the first 3 decimals are identical.

The spelling of 1640712779 in words is "one billion, six hundred forty million, seven hundred twelve thousand, seven hundred seventy-nine".