2011901805 has 48 divisors (see below), whose sum is σ = 3697175664. Its totient is φ = 1008599040.

The previous prime is 2011901797. The next prime is 2011901813. The reversal of 2011901805 is 5081091102.

It is an interprime number because it is at equal distance from previous prime (2011901797) and next prime (2011901813).

It can be written as a sum of positive squares in 8 ways, for example, as 6563844 + 2005337961 = 2562^2 + 44781^2 .

It is not a de Polignac number, because 2011901805 - 2³ = 2011901797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 929925 + ... + 932085.

It is an arithmetic number, because the mean of its divisors is an integer number (77024493).

Almost surely, 2^2011901805 is an apocalyptic number.

It is an amenable number.

2011901805 is a deficient number, since it is larger than the sum of its proper divisors (1685273859).

2011901805 is a wasteful number, since it uses less digits than its factorization.

2011901805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3406 (or 3403 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 2011901805 is about 44854.2283959941. The cubic root of 2011901805 is about 1262.4153311189.

Adding to 2011901805 its reverse (5081091102), we get a palindrome (7092992907).

The spelling of 2011901805 in words is "two billion, eleven million, nine hundred one thousand, eight hundred five".