42400121 has 2 divisors, whose sum is σ = 42400122. Its totient is φ = 42400120.

The previous prime is 42400087. The next prime is 42400139. The reversal of 42400121 is 12100424.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36735721 + 5664400 = 6061^2 + 2380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42400121 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 42400096 and 42400105.

It is not a weakly prime, because it can be changed into another prime (42400181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21200060 + 21200061.

It is an arithmetic number, because the mean of its divisors is an integer number (21200061).

Almost surely, 2^42400121 is an apocalyptic number.

It is an amenable number.

42400121 is a deficient number, since it is larger than the sum of its proper divisors (1).

42400121 is an equidigital number, since it uses as much as digits as its factorization.

42400121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 42400121 is about 6511.5375296469. The cubic root of 42400121 is about 348.7030119589.

Adding to 42400121 its reverse (12100424), we get a palindrome (54500545).

The spelling of 42400121 in words is "forty-two million, four hundred thousand, one hundred twenty-one".