42220021 has 4 divisors (see below), whose sum is σ = 42253632. Its totient is φ = 42186412.

The previous prime is 42219979. The next prime is 42220081. The reversal of 42220021 is 12002224.

42220021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 42220021 - 2⁷ = 42219893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42219983 and 42220010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42220081) 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 in 3 ways as a sum of consecutive naturals, for example, 14845 + ... + 17458.

It is an arithmetic number, because the mean of its divisors is an integer number (10563408).

Almost surely, 2^42220021 is an apocalyptic number.

It is an amenable number.

42220021 is a deficient number, since it is larger than the sum of its proper divisors (33611).

42220021 is a wasteful number, since it uses less digits than its factorization.

42220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33610.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 42220021 is about 6497.6935138555. The cubic root of 42220021 is about 348.2085908705.

Adding to 42220021 its reverse (12002224), we get a palindrome (54222245).

The spelling of 42220021 in words is "forty-two million, two hundred twenty thousand, twenty-one".