19810026 has 12 divisors (see below), whose sum is σ = 42921762. Its totient is φ = 6603336.

The previous prime is 19810013. The next prime is 19810031. The reversal of 19810026 is 62001891.

It can be written as a sum of positive squares in only one way, i.e., 14814801 + 4995225 = 3849^2 + 2235^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 550261 + ... + 550296.

Almost surely, 2^19810026 is an apocalyptic number.

19810026 is an abundant number, since it is smaller than the sum of its proper divisors (23111736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19810026 is a wasteful number, since it uses less digits than its factorization.

19810026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100565 (or 1100562 counting only the distinct ones).

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

The square root of 19810026 is about 4450.8455376479. The cubic root of 19810026 is about 270.5795780413.

The spelling of 19810026 in words is "nineteen million, eight hundred ten thousand, twenty-six".