75016721 has 4 divisors (see below), whose sum is σ = 80787252. Its totient is φ = 69246192.

The previous prime is 75016709. The next prime is 75016813. The reversal of 75016721 is 12761057.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15171025 + 59845696 = 3895^2 + 7736^2 .

It is a cyclic number.

It is not a de Polignac number, because 75016721 - 2⁶ = 75016657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (75016021) 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 3 ways as a sum of consecutive naturals, for example, 2885246 + ... + 2885271.

It is an arithmetic number, because the mean of its divisors is an integer number (20196813).

Almost surely, 2^75016721 is an apocalyptic number.

It is an amenable number.

75016721 is a deficient number, since it is larger than the sum of its proper divisors (5770531).

75016721 is a wasteful number, since it uses less digits than its factorization.

75016721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5770530.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 75016721 is about 8661.2193714280. The cubic root of 75016721 is about 421.7476704057.

Adding to 75016721 its reverse (12761057), we get a palindrome (87777778).

It can be divided in two parts, 750 and 16721, that added together give a palindrome (17471).

The spelling of 75016721 in words is "seventy-five million, sixteen thousand, seven hundred twenty-one".