21420043033 has 2 divisors, whose sum is σ = 21420043034. Its totient is φ = 21420043032.

The previous prime is 21420043013. The next prime is 21420043063. The reversal of 21420043033 is 33034002412.

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., 13271731209 + 8148311824 = 115203^2 + 90268^2 .

It is a cyclic number.

It is not a de Polignac number, because 21420043033 - 2²⁵ = 21386488601 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21420042995 and 21420043013.

It is not a weakly prime, because it can be changed into another prime (21420043003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710021516 + 10710021517.

It is an arithmetic number, because the mean of its divisors is an integer number (10710021517).

Almost surely, 2^21420043033 is an apocalyptic number.

It is an amenable number.

21420043033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420043033 is an equidigital number, since it uses as much as digits as its factorization.

21420043033 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 22.

Adding to 21420043033 its reverse (33034002412), we get a palindrome (54454045445).

The spelling of 21420043033 in words is "twenty-one billion, four hundred twenty million, forty-three thousand, thirty-three".