1990105 has 16 divisors (see below), whose sum is σ = 2724624. Its totient is φ = 1382400.

The previous prime is 1990103. The next prime is 1990111. The reversal of 1990105 is 5010991.

It can be written as a sum of positive squares in 8 ways, for example, as 205209 + 1784896 = 453^2 + 1336^2 .

It is not a de Polignac number, because 1990105 - 2¹ = 1990103 is a prime.

It is a super-2 number, since 2×1990105² = 7921035822050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1990105.

It is not an unprimeable number, because it can be changed into a prime (1990103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205 + ... + 2005.

It is an arithmetic number, because the mean of its divisors is an integer number (170289).

2^1990105 is an apocalyptic number.

It is an amenable number.

1990105 is a deficient number, since it is larger than the sum of its proper divisors (734519).

1990105 is a wasteful number, since it uses less digits than its factorization.

1990105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1836.

The product of its (nonzero) digits is 405, while the sum is 25.

The square root of 1990105 is about 1410.7108137389. The cubic root of 1990105 is about 125.7839793976.

The spelling of 1990105 in words is "one million, nine hundred ninety thousand, one hundred five".