70691981 has 2 divisors, whose sum is σ = 70691982. Its totient is φ = 70691980.

The previous prime is 70691977. The next prime is 70692029. The reversal of 70691981 is 18919607.

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., 52330756 + 18361225 = 7234^2 + 4285^2 .

It is a cyclic number.

It is not a de Polignac number, because 70691981 - 2² = 70691977 is a prime.

It is a super-2 number, since 2×70691981² = 9994712355408722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (70691911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35345990 + 35345991.

It is an arithmetic number, because the mean of its divisors is an integer number (35345991).

Almost surely, 2^70691981 is an apocalyptic number.

It is an amenable number.

70691981 is a deficient number, since it is larger than the sum of its proper divisors (1).

70691981 is an equidigital number, since it uses as much as digits as its factorization.

70691981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 70691981 is about 8407.8523417101. The cubic root of 70691981 is about 413.4821038494.

The spelling of 70691981 in words is "seventy million, six hundred ninety-one thousand, nine hundred eighty-one".