42506221 has 8 divisors (see below), whose sum is σ = 43340024. Its totient is φ = 41679360.

The previous prime is 42506197. The next prime is 42506237. The reversal of 42506221 is 12260524.

It can be written as a sum of positive squares in 4 ways, for example, as 4202500 + 38303721 = 2050^2 + 6189^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 42506221 - 2¹¹ = 42504173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42506192 and 42506201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42506251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11605 + ... + 14821.

It is an arithmetic number, because the mean of its divisors is an integer number (5417503).

Almost surely, 2^42506221 is an apocalyptic number.

It is an amenable number.

42506221 is a deficient number, since it is larger than the sum of its proper divisors (833803).

42506221 is a wasteful number, since it uses less digits than its factorization.

42506221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3471.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 42506221 is about 6519.6795166634. The cubic root of 42506221 is about 348.9936288358.

Adding to 42506221 its reverse (12260524), we get a palindrome (54766745).

The spelling of 42506221 in words is "forty-two million, five hundred six thousand, two hundred twenty-one".