75630721 has 2 divisors, whose sum is σ = 75630722. Its totient is φ = 75630720.

The previous prime is 75630707. The next prime is 75630727. The reversal of 75630721 is 12703657.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68145025 + 7485696 = 8255^2 + 2736^2 .

It is a cyclic number.

It is not a de Polignac number, because 75630721 - 2⁵ = 75630689 is a prime.

It is equal to p_4429147 and since 75630721 and 4429147 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (75630727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37815360 + 37815361.

It is an arithmetic number, because the mean of its divisors is an integer number (37815361).

Almost surely, 2^75630721 is an apocalyptic number.

It is an amenable number.

75630721 is a deficient number, since it is larger than the sum of its proper divisors (1).

75630721 is an equidigital number, since it uses as much as digits as its factorization.

75630721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8820, while the sum is 31.

The square root of 75630721 is about 8696.5924936150. The cubic root of 75630721 is about 422.8951913168.

The spelling of 75630721 in words is "seventy-five million, six hundred thirty thousand, seven hundred twenty-one".