21000421033 has 2 divisors, whose sum is σ = 21000421034. Its totient is φ = 21000421032.

The previous prime is 21000421003. The next prime is 21000421067. The reversal of 21000421033 is 33012400012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20905689744 + 94731289 = 144588^2 + 9733^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000421033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000420998 and 21000421016.

It is not a weakly prime, because it can be changed into another prime (21000421003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500210516 + 10500210517.

It is an arithmetic number, because the mean of its divisors is an integer number (10500210517).

Almost surely, 2^21000421033 is an apocalyptic number.

It is an amenable number.

21000421033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000421033 is an equidigital number, since it uses as much as digits as its factorization.

21000421033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21000421033 its reverse (33012400012), we get a palindrome (54012821045).

The spelling of 21000421033 in words is "twenty-one billion, four hundred twenty-one thousand, thirty-three".