75663981 has 6 divisors (see below), whose sum is σ = 109292430. Its totient is φ = 50442648.

The previous prime is 75663953. The next prime is 75664007. The reversal of 75663981 is 18936657.

It is a happy number.

75663981 is a `hidden beast` number, since 7 + 5 + 6 + 639 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 68211081 + 7452900 = 8259^2 + 2730^2 .

It is not a de Polignac number, because 75663981 - 2⁵ = 75663949 is a prime.

It is a super-2 number, since 2×75663981² = 11450076041536722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75663911) 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 in 5 ways as a sum of consecutive naturals, for example, 4203546 + ... + 4203563.

It is an arithmetic number, because the mean of its divisors is an integer number (18215405).

Almost surely, 2^75663981 is an apocalyptic number.

It is an amenable number.

75663981 is a deficient number, since it is larger than the sum of its proper divisors (33628449).

75663981 is a wasteful number, since it uses less digits than its factorization.

75663981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8407115 (or 8407112 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 75663981 is about 8698.5045266413. The cubic root of 75663981 is about 422.9571742100.

The spelling of 75663981 in words is "seventy-five million, six hundred sixty-three thousand, nine hundred eighty-one".