75138781 has 2 divisors, whose sum is σ = 75138782. Its totient is φ = 75138780.

The previous prime is 75138779. The next prime is 75138871. The reversal of 75138781 is 18783157.

It is a happy number.

Together with next prime (75138871) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73359225 + 1779556 = 8565^2 + 1334^2 .

It is a cyclic number.

It is not a de Polignac number, because 75138781 - 2¹ = 75138779 is a prime.

It is a super-2 number, since 2×75138781² = 11291672820331922, which contains 22 as substring.

Together with 75138779, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75138731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37569390 + 37569391.

It is an arithmetic number, because the mean of its divisors is an integer number (37569391).

Almost surely, 2^75138781 is an apocalyptic number.

It is an amenable number.

75138781 is a deficient number, since it is larger than the sum of its proper divisors (1).

75138781 is an equidigital number, since it uses as much as digits as its factorization.

75138781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 47040, while the sum is 40.

The square root of 75138781 is about 8668.2628594200. The cubic root of 75138781 is about 421.9762888829.

The spelling of 75138781 in words is "seventy-five million, one hundred thirty-eight thousand, seven hundred eighty-one".