75000721 has 2 divisors, whose sum is σ = 75000722. Its totient is φ = 75000720.

The previous prime is 75000703. The next prime is 75000743. The reversal of 75000721 is 12700057.

It is an a-pointer prime, because the next prime (75000743) can be obtained adding 75000721 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58354321 + 16646400 = 7639^2 + 4080^2 .

It is a cyclic number.

It is not a de Polignac number, because 75000721 - 2¹³ = 74992529 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 75000692 and 75000701.

It is not a weakly prime, because it can be changed into another prime (75000421) 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 as a sum of consecutive naturals, namely, 37500360 + 37500361.

It is an arithmetic number, because the mean of its divisors is an integer number (37500361).

Almost surely, 2^75000721 is an apocalyptic number.

It is an amenable number.

75000721 is a deficient number, since it is larger than the sum of its proper divisors (1).

75000721 is an equidigital number, since it uses as much as digits as its factorization.

75000721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 490, while the sum is 22.

The square root of 75000721 is about 8660.2956646988. The cubic root of 75000721 is about 421.7176840131.

Adding to 75000721 its reverse (12700057), we get a palindrome (87700778).

The spelling of 75000721 in words is "seventy-five million, seven hundred twenty-one", and thus it is an aban number.