42872021 has 2 divisors, whose sum is σ = 42872022. Its totient is φ = 42872020.

The previous prime is 42872017. The next prime is 42872029. The reversal of 42872021 is 12027824.

42872021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33477796 + 9394225 = 5786^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 42872021 - 2² = 42872017 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42872029) 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 as a sum of consecutive naturals, namely, 21436010 + 21436011.

It is an arithmetic number, because the mean of its divisors is an integer number (21436011).

Almost surely, 2^42872021 is an apocalyptic number.

It is an amenable number.

42872021 is a deficient number, since it is larger than the sum of its proper divisors (1).

42872021 is an equidigital number, since it uses as much as digits as its factorization.

42872021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 42872021 is about 6547.6729454059. The cubic root of 42872021 is about 349.9918936898.

Adding to 42872021 its reverse (12027824), we get a palindrome (54899845).

The spelling of 42872021 in words is "forty-two million, eight hundred seventy-two thousand, twenty-one".