42121521 has 24 divisors (see below), whose sum is σ = 65932776. Its totient is φ = 25758720.

The previous prime is 42121501. The next prime is 42121549. The reversal of 42121521 is 12512124.

It can be written as a sum of positive squares in 4 ways, for example, as 5688225 + 36433296 = 2385^2 + 6036^2 .

It is a de Polignac number, because none of the positive numbers 2^k-42121521 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42121494 and 42121503.

It is not an unprimeable number, because it can be changed into a prime (42121501) 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 in 23 ways as a sum of consecutive naturals, for example, 19201 + ... + 21281.

It is an arithmetic number, because the mean of its divisors is an integer number (2747199).

Almost surely, 2^42121521 is an apocalyptic number.

It is an amenable number.

42121521 is a deficient number, since it is larger than the sum of its proper divisors (23811255).

42121521 is a wasteful number, since it uses less digits than its factorization.

42121521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2273 (or 2270 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 42121521 is about 6490.1094751938. The cubic root of 42121521 is about 347.9375878957.

Adding to 42121521 its reverse (12512124), we get a palindrome (54633645).

The spelling of 42121521 in words is "forty-two million, one hundred twenty-one thousand, five hundred twenty-one".