42228421 has 2 divisors, whose sum is σ = 42228422. Its totient is φ = 42228420.

The previous prime is 42228371. The next prime is 42228443. The reversal of 42228421 is 12482224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37344321 + 4884100 = 6111^2 + 2210^2 .

It is a cyclic number.

It is not a de Polignac number, because 42228421 - 2¹³ = 42220229 is a prime.

It is equal to p_2560660 and since 42228421 and 2560660 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42228721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21114210 + 21114211.

It is an arithmetic number, because the mean of its divisors is an integer number (21114211).

Almost surely, 2^42228421 is an apocalyptic number.

It is an amenable number.

42228421 is a deficient number, since it is larger than the sum of its proper divisors (1).

42228421 is an equidigital number, since it uses as much as digits as its factorization.

42228421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2048, while the sum is 25.

The square root of 42228421 is about 6498.3398649193. The cubic root of 42228421 is about 348.2316822707.

The spelling of 42228421 in words is "forty-two million, two hundred twenty-eight thousand, four hundred twenty-one".