1808923905 has 12 divisors (see below), whose sum is σ = 3135468180. Its totient is φ = 964759392.

The previous prime is 1808923877. The next prime is 1808923931. The reversal of 1808923905 is 5093298081.

It is a happy number.

1808923905 is a `hidden beast` number, since 180 + 89 + 2 + 390 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1075380849 + 733543056 = 32793^2 + 27084^2 .

It is not a de Polignac number, because 1808923905 - 2¹¹ = 1808921857 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 40198309 = 1808923905 / (1 + 8 + 0 + 8 + 9 + 2 + 3 + 9 + 0 + 5).

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 20099110 + ... + 20099199.

It is an arithmetic number, because the mean of its divisors is an integer number (261289015).

Almost surely, 2^1808923905 is an apocalyptic number.

1808923905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1808923905 is a deficient number, since it is larger than the sum of its proper divisors (1326544275).

1808923905 is a wasteful number, since it uses less digits than its factorization.

1808923905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40198320 (or 40198317 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 1808923905 is about 42531.4460722887. The cubic root of 1808923905 is about 1218.4473451234.

The spelling of 1808923905 in words is "one billion, eight hundred eight million, nine hundred twenty-three thousand, nine hundred five".