75565991 has 2 divisors, whose sum is σ = 75565992. Its totient is φ = 75565990.

The previous prime is 75565981. The next prime is 75565999. The reversal of 75565991 is 19956557.

It is a strong prime.

It is an emirp because it is prime and its reverse (19956557) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 75565991 - 2¹⁸ = 75303847 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75565999) 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 as a sum of consecutive naturals, namely, 37782995 + 37782996.

It is an arithmetic number, because the mean of its divisors is an integer number (37782996).

Almost surely, 2^75565991 is an apocalyptic number.

75565991 is a deficient number, since it is larger than the sum of its proper divisors (1).

75565991 is an equidigital number, since it uses as much as digits as its factorization.

75565991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 425250, while the sum is 47.

The square root of 75565991 is about 8692.8701244181. The cubic root of 75565991 is about 422.7745092332.

The spelling of 75565991 in words is "seventy-five million, five hundred sixty-five thousand, nine hundred ninety-one".