75243521 has 4 divisors (see below), whose sum is σ = 75264000. Its totient is φ = 75223044.

The previous prime is 75243503. The next prime is 75243523. The reversal of 75243521 is 12534257.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12534257 = 503 ⋅24919.

It is a cyclic number.

It is not a de Polignac number, because 75243521 - 2¹⁸ = 74981377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (75243523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3041 + ... + 12638.

It is an arithmetic number, because the mean of its divisors is an integer number (18816000).

Almost surely, 2^75243521 is an apocalyptic number.

It is an amenable number.

75243521 is a deficient number, since it is larger than the sum of its proper divisors (20479).

75243521 is a wasteful number, since it uses less digits than its factorization.

75243521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20478.

The product of its digits is 8400, while the sum is 29.

The square root of 75243521 is about 8674.3023350584. The cubic root of 75243521 is about 422.1722696855.

Adding to 75243521 its reverse (12534257), we get a palindrome (87777778).

The spelling of 75243521 in words is "seventy-five million, two hundred forty-three thousand, five hundred twenty-one".