42661221 has 16 divisors (see below), whose sum is σ = 57729024. Its totient is φ = 28020464.

The previous prime is 42661207. The next prime is 42661243. The reversal of 42661221 is 12216624.

It is a cyclic number.

It is not a de Polignac number, because 42661221 - 2¹³ = 42653029 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 42661191 and 42661200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42661271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111196 + ... + 111578.

It is an arithmetic number, because the mean of its divisors is an integer number (3608064).

Almost surely, 2^42661221 is an apocalyptic number.

It is an amenable number.

42661221 is a deficient number, since it is larger than the sum of its proper divisors (15067803).

42661221 is a wasteful number, since it uses less digits than its factorization.

42661221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840.

The product of its digits is 1152, while the sum is 24.

The square root of 42661221 is about 6531.5557871000. Note that the first 3 decimals coincide. The cubic root of 42661221 is about 349.4173189244.

Adding to 42661221 its reverse (12216624), we get a palindrome (54877845).

The spelling of 42661221 in words is "forty-two million, six hundred sixty-one thousand, two hundred twenty-one".