42508421 has 2 divisors, whose sum is σ = 42508422. Its totient is φ = 42508420.

The previous prime is 42508391. The next prime is 42508423. The reversal of 42508421 is 12480524.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24750625 + 17757796 = 4975^2 + 4214^2 .

It is a cyclic number.

It is not a de Polignac number, because 42508421 - 2⁶ = 42508357 is a prime.

Together with 42508423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42508423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21254210 + 21254211.

It is an arithmetic number, because the mean of its divisors is an integer number (21254211).

Almost surely, 2^42508421 is an apocalyptic number.

It is an amenable number.

42508421 is a deficient number, since it is larger than the sum of its proper divisors (1).

42508421 is an equidigital number, since it uses as much as digits as its factorization.

42508421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 42508421 is about 6519.8482344300. The cubic root of 42508421 is about 348.9996497015. Note that the first 3 decimals are identical.

Adding to 42508421 its reverse (12480524), we get a palindrome (54988945).

The spelling of 42508421 in words is "forty-two million, five hundred eight thousand, four hundred twenty-one".