75199981 has 2 divisors, whose sum is σ = 75199982. Its totient is φ = 75199980.

The previous prime is 75199961. The next prime is 75200003. The reversal of 75199981 is 18999157.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42367081 + 32832900 = 6509^2 + 5730^2 .

It is a cyclic number.

It is not a de Polignac number, because 75199981 - 2²³ = 66811373 is a prime.

It is a super-2 number, since 2×75199981² = 11310074284800722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75199961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37599990 + 37599991.

It is an arithmetic number, because the mean of its divisors is an integer number (37599991).

Almost surely, 2^75199981 is an apocalyptic number.

It is an amenable number.

75199981 is a deficient number, since it is larger than the sum of its proper divisors (1).

75199981 is an equidigital number, since it uses as much as digits as its factorization.

75199981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 49.

The square root of 75199981 is about 8671.7922599656. The cubic root of 75199981 is about 422.0908233496.

The spelling of 75199981 in words is "seventy-five million, one hundred ninety-nine thousand, nine hundred eighty-one".