20671919 has 2 divisors, whose sum is σ = 20671920. Its totient is φ = 20671918.

The previous prime is 20671907. The next prime is 20671927. The reversal of 20671919 is 91917602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20671919 - 2²⁴ = 3894703 is a prime.

It is a super-3 number, since 3×20671919³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20671939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10335959 + 10335960.

It is an arithmetic number, because the mean of its divisors is an integer number (10335960).

Almost surely, 2^20671919 is an apocalyptic number.

20671919 is a deficient number, since it is larger than the sum of its proper divisors (1).

20671919 is an equidigital number, since it uses as much as digits as its factorization.

20671919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 20671919 is about 4546.6382086108. The cubic root of 20671919 is about 274.4481229720.

The spelling of 20671919 in words is "twenty million, six hundred seventy-one thousand, nine hundred nineteen".