75109981 has 2 divisors, whose sum is σ = 75109982. Its totient is φ = 75109980.

The previous prime is 75109943. The next prime is 75109999. The reversal of 75109981 is 18990157.

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., 50765625 + 24344356 = 7125^2 + 4934^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-75109981 is a prime.

It is a super-2 number, since 2×75109981² = 11283018491640722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75109081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37554990 + 37554991.

It is an arithmetic number, because the mean of its divisors is an integer number (37554991).

Almost surely, 2^75109981 is an apocalyptic number.

It is an amenable number.

75109981 is a deficient number, since it is larger than the sum of its proper divisors (1).

75109981 is an equidigital number, since it uses as much as digits as its factorization.

75109981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 75109981 is about 8666.6014677035. The cubic root of 75109981 is about 421.9223687900.

The spelling of 75109981 in words is "seventy-five million, one hundred nine thousand, nine hundred eighty-one".