42540221 has 4 divisors (see below), whose sum is σ = 44779200. Its totient is φ = 40301244.

The previous prime is 42540191. The next prime is 42540227. The reversal of 42540221 is 12204524.

It is a happy number.

42540221 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 42540221 - 2¹⁰ = 42539197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42540193 and 42540202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42540227) 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, 1119461 + ... + 1119498.

It is an arithmetic number, because the mean of its divisors is an integer number (11194800).

Almost surely, 2^42540221 is an apocalyptic number.

It is an amenable number.

42540221 is a deficient number, since it is larger than the sum of its proper divisors (2238979).

42540221 is a wasteful number, since it uses less digits than its factorization.

42540221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2238978.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 42540221 is about 6522.2864855816. The cubic root of 42540221 is about 349.0866553840.

Adding to 42540221 its reverse (12204524), we get a palindrome (54744745).

The spelling of 42540221 in words is "forty-two million, five hundred forty thousand, two hundred twenty-one".