1640879 has 2 divisors, whose sum is σ = 1640880. Its totient is φ = 1640878.

The previous prime is 1640869. The next prime is 1640887. The reversal of 1640879 is 9780461.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1640879 - 2⁸ = 1640623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820439 + 820440.

It is an arithmetic number, because the mean of its divisors is an integer number (820440).

2^1640879 is an apocalyptic number.

1640879 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640879 is an equidigital number, since it uses as much as digits as its factorization.

1640879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 1640879 is about 1280.9679933550. The cubic root of 1640879 is about 117.9484357679.

The spelling of 1640879 in words is "one million, six hundred forty thousand, eight hundred seventy-nine".