42424021 has 2 divisors, whose sum is σ = 42424022. Its totient is φ = 42424020.

The previous prime is 42424007. The next prime is 42424037. The reversal of 42424021 is 12042424.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27447121 + 14976900 = 5239^2 + 3870^2 .

It is a cyclic number.

It is not a de Polignac number, because 42424021 - 2⁹ = 42423509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42424021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42424001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21212010 + 21212011.

It is an arithmetic number, because the mean of its divisors is an integer number (21212011).

Almost surely, 2^42424021 is an apocalyptic number.

It is an amenable number.

42424021 is a deficient number, since it is larger than the sum of its proper divisors (1).

42424021 is an equidigital number, since it uses as much as digits as its factorization.

42424021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 42424021 is about 6513.3724751468. The cubic root of 42424021 is about 348.7685183488.

Adding to 42424021 its reverse (12042424), we get a palindrome (54466445).

The spelling of 42424021 in words is "forty-two million, four hundred twenty-four thousand, twenty-one".