1645864859 has 2 divisors, whose sum is σ = 1645864860. Its totient is φ = 1645864858.

The previous prime is 1645864853. The next prime is 1645864879. The reversal of 1645864859 is 9584685461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1645864859 - 2²⁴ = 1629087643 is a prime.

It is a super-2 number, since 2×1645864859² = 5417742268182179762, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1645864853) 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 as a sum of consecutive naturals, namely, 822932429 + 822932430.

It is an arithmetic number, because the mean of its divisors is an integer number (822932430).

Almost surely, 2^1645864859 is an apocalyptic number.

1645864859 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645864859 is an equidigital number, since it uses as much as digits as its factorization.

1645864859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8294400, while the sum is 56.

The square root of 1645864859 is about 40569.2600252950. The cubic root of 1645864859 is about 1180.6777823547.

The spelling of 1645864859 in words is "one billion, six hundred forty-five million, eight hundred sixty-four thousand, eight hundred fifty-nine".