1901821085 has 4 divisors (see below), whose sum is σ = 2282185308. Its totient is φ = 1521456864.

The previous prime is 1901821069. The next prime is 1901821111. The reversal of 1901821085 is 5801281091.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5801281091 = 389 ⋅14913319.

It can be written as a sum of positive squares in 2 ways, for example, as 1122183001 + 779638084 = 33499^2 + 27922^2 .

It is a cyclic number.

It is not a de Polignac number, because 1901821085 - 2⁴ = 1901821069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190182104 + ... + 190182113.

It is an arithmetic number, because the mean of its divisors is an integer number (570546327).

Almost surely, 2^1901821085 is an apocalyptic number.

It is an amenable number.

1901821085 is a deficient number, since it is larger than the sum of its proper divisors (380364223).

1901821085 is an equidigital number, since it uses as much as digits as its factorization.

1901821085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380364222.

The product of its (nonzero) digits is 5760, while the sum is 35.

The square root of 1901821085 is about 43609.8737099754. The cubic root of 1901821085 is about 1238.9579098141.

The spelling of 1901821085 in words is "one billion, nine hundred one million, eight hundred twenty-one thousand, eighty-five".