1817999905 has 16 divisors (see below), whose sum is σ = 2226553920. Its totient is φ = 1424524608.

The previous prime is 1817999893. The next prime is 1817999917. The reversal of 1817999905 is 5099997181.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1817999893) and next prime (1817999917).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1817999905 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1817999905.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158494 + ... + 169576.

It is an arithmetic number, because the mean of its divisors is an integer number (139159620).

Almost surely, 2^1817999905 is an apocalyptic number.

It is an amenable number.

1817999905 is a deficient number, since it is larger than the sum of its proper divisors (408554015).

1817999905 is a wasteful number, since it uses less digits than its factorization.

1817999905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11760.

The product of its (nonzero) digits is 1837080, while the sum is 58.

The square root of 1817999905 is about 42638.0100966262. The cubic root of 1817999905 is about 1220.4817377737.

The spelling of 1817999905 in words is "one billion, eight hundred seventeen million, nine hundred ninety-nine thousand, nine hundred five".