1999905 has 8 divisors (see below), whose sum is σ = 3199872. Its totient is φ = 1066608.

The previous prime is 1999891. The next prime is 1999957. The reversal of 1999905 is 5099991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1999905 - 2⁴ = 1999889 is a prime.

1999905 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66649 + ... + 66678.

It is an arithmetic number, because the mean of its divisors is an integer number (399984).

2^1999905 is an apocalyptic number.

1999905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1999905 is a deficient number, since it is larger than the sum of its proper divisors (1199967).

1999905 is a wasteful number, since it uses less digits than its factorization.

1999905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133335.

The product of its (nonzero) digits is 32805, while the sum is 42.

The square root of 1999905 is about 1414.1799744021. The cubic root of 1999905 is about 125.9901100829.

The spelling of 1999905 in words is "one million, nine hundred ninety-nine thousand, nine hundred five".