75705781 has 2 divisors, whose sum is σ = 75705782. Its totient is φ = 75705780.

The previous prime is 75705739. The next prime is 75705787. The reversal of 75705781 is 18750757.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51351556 + 24354225 = 7166^2 + 4935^2 .

It is an emirp because it is prime and its reverse (18750757) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 75705781 - 2¹⁹ = 75181493 is a prime.

It is a super-2 number, since 2×75705781² = 11462730553639922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75705787) 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, 37852890 + 37852891.

It is an arithmetic number, because the mean of its divisors is an integer number (37852891).

Almost surely, 2^75705781 is an apocalyptic number.

It is an amenable number.

75705781 is a deficient number, since it is larger than the sum of its proper divisors (1).

75705781 is an equidigital number, since it uses as much as digits as its factorization.

75705781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68600, while the sum is 40.

The square root of 75705781 is about 8700.9069067540. The cubic root of 75705781 is about 423.0350463802.

The spelling of 75705781 in words is "seventy-five million, seven hundred five thousand, seven hundred eighty-one".