42012521 has 2 divisors, whose sum is σ = 42012522. Its totient is φ = 42012520.

The previous prime is 42012511. The next prime is 42012541. The reversal of 42012521 is 12521024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35581225 + 6431296 = 5965^2 + 2536^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42012521 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42012521.

It is not a weakly prime, because it can be changed into another prime (42012511) 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, 21006260 + 21006261.

It is an arithmetic number, because the mean of its divisors is an integer number (21006261).

Almost surely, 2^42012521 is an apocalyptic number.

It is an amenable number.

42012521 is a deficient number, since it is larger than the sum of its proper divisors (1).

42012521 is an equidigital number, since it uses as much as digits as its factorization.

42012521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 42012521 is about 6481.7066425441. The cubic root of 42012521 is about 347.6372033817.

Subtracting from 42012521 its product of nonzero digits (160), we obtain a triangular number (42012361 = T₉₁₆₆).

Adding to 42012521 its reverse (12521024), we get a palindrome (54533545).

The spelling of 42012521 in words is "forty-two million, twelve thousand, five hundred twenty-one".