75100721 has 4 divisors (see below), whose sum is σ = 76129572. Its totient is φ = 74071872.

The previous prime is 75100717. The next prime is 75100723. The reversal of 75100721 is 12700157.

It is a happy number.

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 41460721 + 33640000 = 6439^2 + 5800^2 .

It is a cyclic number.

It is not a de Polignac number, because 75100721 - 2² = 75100717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (75100723) 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, 514316 + ... + 514461.

It is an arithmetic number, because the mean of its divisors is an integer number (19032393).

Almost surely, 2^75100721 is an apocalyptic number.

It is an amenable number.

75100721 is a deficient number, since it is larger than the sum of its proper divisors (1028851).

75100721 is a wasteful number, since it uses less digits than its factorization.

75100721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1028850.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 75100721 is about 8666.0672164483. The cubic root of 75100721 is about 421.9050290541.

Adding to 75100721 its reverse (12700157), we get a palindrome (87800878).

The spelling of 75100721 in words is "seventy-five million, one hundred thousand, seven hundred twenty-one".