75971981 has 2 divisors, whose sum is σ = 75971982. Its totient is φ = 75971980.

The previous prime is 75971977. The next prime is 75971983. The reversal of 75971981 is 18917957.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68326756 + 7645225 = 8266^2 + 2765^2 .

It is a cyclic number.

It is not a de Polignac number, because 75971981 - 2² = 75971977 is a prime.

It is a super-2 number, since 2×75971981² = 11543483794128722, which contains 22 as substring.

Together with 75971983, 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 (75971983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37985990 + 37985991.

It is an arithmetic number, because the mean of its divisors is an integer number (37985991).

Almost surely, 2^75971981 is an apocalyptic number.

It is an amenable number.

75971981 is a deficient number, since it is larger than the sum of its proper divisors (1).

75971981 is an equidigital number, since it uses as much as digits as its factorization.

75971981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 158760, while the sum is 47.

The square root of 75971981 is about 8716.1907390786. The cubic root of 75971981 is about 423.5302978426.

The spelling of 75971981 in words is "seventy-five million, nine hundred seventy-one thousand, nine hundred eighty-one".