42142421 has 2 divisors, whose sum is σ = 42142422. Its totient is φ = 42142420.

The previous prime is 42142403. The next prime is 42142427. The reversal of 42142421 is 12424124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39627025 + 2515396 = 6295^2 + 1586^2 .

It is a cyclic number.

It is not a de Polignac number, because 42142421 - 2⁶ = 42142357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 42142393 and 42142402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42142427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21071210 + 21071211.

It is an arithmetic number, because the mean of its divisors is an integer number (21071211).

Almost surely, 2^42142421 is an apocalyptic number.

It is an amenable number.

42142421 is a deficient number, since it is larger than the sum of its proper divisors (1).

42142421 is an equidigital number, since it uses as much as digits as its factorization.

42142421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 512, while the sum is 20.

The square root of 42142421 is about 6491.7194178430. The cubic root of 42142421 is about 347.9951253336.

Adding to 42142421 its reverse (12424124), we get a palindrome (54566545).

The spelling of 42142421 in words is "forty-two million, one hundred forty-two thousand, four hundred twenty-one".