20421073819 has 2 divisors, whose sum is σ = 20421073820. Its totient is φ = 20421073818.

The previous prime is 20421073807. The next prime is 20421073837. The reversal of 20421073819 is 91837012402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20421073819 - 2¹⁵ = 20421041051 is a prime.

It is a super-2 number, since 2×20421073819² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20421073019) 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, 10210536909 + 10210536910.

It is an arithmetic number, because the mean of its divisors is an integer number (10210536910).

Almost surely, 2^20421073819 is an apocalyptic number.

20421073819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421073819 is an equidigital number, since it uses as much as digits as its factorization.

20421073819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The spelling of 20421073819 in words is "twenty billion, four hundred twenty-one million, seventy-three thousand, eight hundred nineteen".