20819473 has 4 divisors (see below), whose sum is σ = 20831668. Its totient is φ = 20807280.

The previous prime is 20819467. The next prime is 20819521. The reversal of 20819473 is 37491802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37491802 = 2 ⋅18745901.

It can be written as a sum of positive squares in 2 ways, for example, as 7033104 + 13786369 = 2652^2 + 3713^2 .

It is a cyclic number.

It is not a de Polignac number, because 20819473 - 2⁹ = 20818961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20819413) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3018 + ... + 7123.

It is an arithmetic number, because the mean of its divisors is an integer number (5207917).

Almost surely, 2^20819473 is an apocalyptic number.

It is an amenable number.

20819473 is a deficient number, since it is larger than the sum of its proper divisors (12195).

20819473 is a wasteful number, since it uses less digits than its factorization.

20819473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12194.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 20819473 is about 4562.8360698145. The cubic root of 20819473 is about 275.0995694541.

The spelling of 20819473 in words is "twenty million, eight hundred nineteen thousand, four hundred seventy-three".