71656381 has 2 divisors, whose sum is σ = 71656382. Its totient is φ = 71656380.

The previous prime is 71656363. The next prime is 71656421. The reversal of 71656381 is 18365617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36360900 + 35295481 = 6030^2 + 5941^2 .

It is a cyclic number.

It is not a de Polignac number, because 71656381 - 2⁵ = 71656349 is a prime.

It is a super-2 number, since 2×71656381² = 10269273876034322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 71656381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71656181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35828190 + 35828191.

It is an arithmetic number, because the mean of its divisors is an integer number (35828191).

Almost surely, 2^71656381 is an apocalyptic number.

It is an amenable number.

71656381 is a deficient number, since it is larger than the sum of its proper divisors (1).

71656381 is an equidigital number, since it uses as much as digits as its factorization.

71656381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 37.

The square root of 71656381 is about 8465.0092144073. The cubic root of 71656381 is about 415.3538975711.

The spelling of 71656381 in words is "seventy-one million, six hundred fifty-six thousand, three hundred eighty-one".