70981 has 2 divisors, whose sum is σ = 70982. Its totient is φ = 70980.

The previous prime is 70979. The next prime is 70991. The reversal of 70981 is 18907.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70756 + 225 = 266^2 + 15^2 .

It is a cyclic number.

It is not a de Polignac number, because 70981 - 2¹ = 70979 is a prime.

It is a super-2 number, since 2×70981² = 10076604722, which contains 22 as substring.

Together with 70979, it forms a pair of twin primes.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (70901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35490 + 35491.

It is an arithmetic number, because the mean of its divisors is an integer number (35491).

2⁷⁰⁹⁸¹ is an apocalyptic number.

70981 is the 169-th centered pentagonal number.

It is an amenable number.

70981 is a deficient number, since it is larger than the sum of its proper divisors (1).

70981 is an equidigital number, since it uses as much as digits as its factorization.

70981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 70981 is about 266.4225966392. The cubic root of 70981 is about 41.4044834775.

The spelling of 70981 in words is "seventy thousand, nine hundred eighty-one".