71956981 has 2 divisors, whose sum is σ = 71956982. Its totient is φ = 71956980.

The previous prime is 71956979. The next prime is 71956993. The reversal of 71956981 is 18965917.

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., 44488900 + 27468081 = 6670^2 + 5241^2 .

It is a cyclic number.

It is not a de Polignac number, because 71956981 - 2¹ = 71956979 is a prime.

It is a super-2 number, since 2×71956981² = 10355614229268722, which contains 22 as substring.

Together with 71956979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71956961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35978490 + 35978491.

It is an arithmetic number, because the mean of its divisors is an integer number (35978491).

Almost surely, 2^71956981 is an apocalyptic number.

It is an amenable number.

71956981 is a deficient number, since it is larger than the sum of its proper divisors (1).

71956981 is an equidigital number, since it uses as much as digits as its factorization.

71956981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 46.

The square root of 71956981 is about 8482.7460765957. The cubic root of 71956981 is about 415.9338933571.

The spelling of 71956981 in words is "seventy-one million, nine hundred fifty-six thousand, nine hundred eighty-one".