2019861 has 6 divisors (see below), whose sum is σ = 2917590. Its totient is φ = 1346568.

The previous prime is 2019859. The next prime is 2019869. The reversal of 2019861 is 1689102.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 820836 = 1095^2 + 906^2 .

It is not a de Polignac number, because 2019861 - 2¹ = 2019859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2019869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 112206 + ... + 112223.

It is an arithmetic number, because the mean of its divisors is an integer number (486265).

2^2019861 is an apocalyptic number.

It is an amenable number.

2019861 is a deficient number, since it is larger than the sum of its proper divisors (897729).

2019861 is a wasteful number, since it uses less digits than its factorization.

2019861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224435 (or 224432 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 2019861 is about 1421.2181394846. The cubic root of 2019861 is about 126.4077869008.

It can be divided in two parts, 20 and 19861, that added together give a square (19881 = 141²).

The spelling of 2019861 in words is "two million, nineteen thousand, eight hundred sixty-one".