42421221 has 12 divisors (see below), whose sum is σ = 61352460. Its totient is φ = 28245120.

The previous prime is 42421219. The next prime is 42421231. The reversal of 42421221 is 12212424.

42421221 is a `hidden beast` number, since 424 + 21 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 23184225 + 19236996 = 4815^2 + 4386^2 .

It is not a de Polignac number, because 42421221 - 2¹ = 42421219 is a prime.

It is a super-2 number, since 2×42421221² = 3599119982261682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 42421194 and 42421203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42421201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5965 + ... + 10973.

It is an arithmetic number, because the mean of its divisors is an integer number (5112705).

Almost surely, 2^42421221 is an apocalyptic number.

It is an amenable number.

42421221 is a deficient number, since it is larger than the sum of its proper divisors (18931239).

42421221 is a wasteful number, since it uses less digits than its factorization.

42421221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5956 (or 5953 counting only the distinct ones).

The product of its digits is 256, while the sum is 18.

The square root of 42421221 is about 6513.1575291866. The cubic root of 42421221 is about 348.7608452326.

Adding to 42421221 its reverse (12212424), we get a palindrome (54633645).

The spelling of 42421221 in words is "forty-two million, four hundred twenty-one thousand, two hundred twenty-one".