42210521 has 2 divisors, whose sum is σ = 42210522. Its totient is φ = 42210520.

The previous prime is 42210431. The next prime is 42210523. The reversal of 42210521 is 12501224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29855296 + 12355225 = 5464^2 + 3515^2 .

It is a cyclic number.

It is not a de Polignac number, because 42210521 - 2¹⁸ = 41948377 is a prime.

Together with 42210523, it forms a pair of twin primes.

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 42210521.

It is not a weakly prime, because it can be changed into another prime (42210523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21105260 + 21105261.

It is an arithmetic number, because the mean of its divisors is an integer number (21105261).

Almost surely, 2^42210521 is an apocalyptic number.

It is an amenable number.

42210521 is a deficient number, since it is larger than the sum of its proper divisors (1).

42210521 is an equidigital number, since it uses as much as digits as its factorization.

42210521 is an evil number, because the sum of its binary digits is even.

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

The square root of 42210521 is about 6496.9624440965. The cubic root of 42210521 is about 348.1824719054.

Adding to 42210521 its reverse (12501224), we get a palindrome (54711745).

The spelling of 42210521 in words is "forty-two million, two hundred ten thousand, five hundred twenty-one".