1681999999 has 2 divisors, whose sum is σ = 1682000000. Its totient is φ = 1681999998.

The previous prime is 1681999993. The next prime is 1682000017. The reversal of 1681999999 is 9999991861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1681999999 - 2⁵ = 1681999967 is a prime.

1681999999 is a modest number, since divided by 99999 gives 16819 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1681999993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840999999 + 841000000.

It is an arithmetic number, because the mean of its divisors is an integer number (841000000).

Almost surely, 2^1681999999 is an apocalyptic number.

1681999999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681999999 is an equidigital number, since it uses as much as digits as its factorization.

1681999999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25509168, while the sum is 70.

The square root of 1681999999 is about 41012.1932966283. The cubic root of 1681999999 is about 1189.2559430798.

The spelling of 1681999999 in words is "one billion, six hundred eighty-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".