75051721 has 4 divisors (see below), whose sum is σ = 75100032. Its totient is φ = 75003412.

The previous prime is 75051709. The next prime is 75051733. The reversal of 75051721 is 12715057.

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: 12715057 = 43 ⋅295699.

It is an interprime number because it is at equal distance from previous prime (75051709) and next prime (75051733).

It is a cyclic number.

It is not a de Polignac number, because 75051721 - 2⁷ = 75051593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 75051721.

It is not an unprimeable number, because it can be changed into a prime (75051701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21745 + ... + 24958.

It is an arithmetic number, because the mean of its divisors is an integer number (18775008).

Almost surely, 2^75051721 is an apocalyptic number.

It is an amenable number.

75051721 is a deficient number, since it is larger than the sum of its proper divisors (48311).

75051721 is a wasteful number, since it uses less digits than its factorization.

75051721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48310.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 75051721 is about 8663.2396365332. The cubic root of 75051721 is about 421.8132507776.

Adding to 75051721 its reverse (12715057), we get a palindrome (87766778).

The spelling of 75051721 in words is "seventy-five million, fifty-one thousand, seven hundred twenty-one".