42550421 has 2 divisors, whose sum is σ = 42550422. Its totient is φ = 42550420.

The previous prime is 42550399. The next prime is 42550447. The reversal of 42550421 is 12405524.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33466225 + 9084196 = 5785^2 + 3014^2 .

It is a cyclic number.

It is not a de Polignac number, because 42550421 - 2⁶ = 42550357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42550451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21275210 + 21275211.

It is an arithmetic number, because the mean of its divisors is an integer number (21275211).

Almost surely, 2^42550421 is an apocalyptic number.

It is an amenable number.

42550421 is a deficient number, since it is larger than the sum of its proper divisors (1).

42550421 is an equidigital number, since it uses as much as digits as its factorization.

42550421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 42550421 is about 6523.0683730895. The cubic root of 42550421 is about 349.1145536823.

Adding to 42550421 its reverse (12405524), we get a palindrome (54955945).

The spelling of 42550421 in words is "forty-two million, five hundred fifty thousand, four hundred twenty-one".