2019681 has 32 divisors (see below), whose sum is σ = 3276800. Its totient is φ = 1224720.

The previous prime is 2019679. The next prime is 2019707. The reversal of 2019681 is 1869102.

It is not a de Polignac number, because 2019681 - 2¹ = 2019679 is a prime.

It is a super-2 number, since 2×2019681² = 8158222683522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2019181) 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 31 ways as a sum of consecutive naturals, for example, 15840 + ... + 15966.

It is an arithmetic number, because the mean of its divisors is an integer number (102400).

2^2019681 is an apocalyptic number.

It is an amenable number.

2019681 is a deficient number, since it is larger than the sum of its proper divisors (1257119).

2019681 is a wasteful number, since it uses less digits than its factorization.

2019681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 180 counting only the distinct ones).

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

The square root of 2019681 is about 1421.1548121158. The cubic root of 2019681 is about 126.4040318441.

It can be divided in two parts, 20 and 19681, that added together give a triangular number (19701 = T₁₉₈).

The spelling of 2019681 in words is "two million, nineteen thousand, six hundred eighty-one".