19828681 has 4 divisors (see below), whose sum is σ = 20995092. Its totient is φ = 18662272.

The previous prime is 19828657. The next prime is 19828693. The reversal of 19828681 is 18682891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18682891 = 37 ⋅504943.

It can be written as a sum of positive squares in 2 ways, for example, as 12538681 + 7290000 = 3541^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 19828681 - 2⁵ = 19828649 is a prime.

It is a super-2 number, since 2×19828681² = 786353180399522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19828481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 583180 + ... + 583213.

It is an arithmetic number, because the mean of its divisors is an integer number (5248773).

Almost surely, 2^19828681 is an apocalyptic number.

It is an amenable number.

19828681 is a deficient number, since it is larger than the sum of its proper divisors (1166411).

19828681 is a wasteful number, since it uses less digits than its factorization.

19828681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166410.

The product of its digits is 55296, while the sum is 43.

The square root of 19828681 is about 4452.9407137306. The cubic root of 19828681 is about 270.6644858620.

The spelling of 19828681 in words is "nineteen million, eight hundred twenty-eight thousand, six hundred eighty-one".