71681861 has 2 divisors, whose sum is σ = 71681862. Its totient is φ = 71681860.

The previous prime is 71681837. The next prime is 71681867. The reversal of 71681861 is 16818617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65772100 + 5909761 = 8110^2 + 2431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71681861 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71681867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35840930 + 35840931.

It is an arithmetic number, because the mean of its divisors is an integer number (35840931).

Almost surely, 2^71681861 is an apocalyptic number.

It is an amenable number.

71681861 is a deficient number, since it is larger than the sum of its proper divisors (1).

71681861 is an equidigital number, since it uses as much as digits as its factorization.

71681861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 38.

The square root of 71681861 is about 8466.5140996753. The cubic root of 71681861 is about 415.4031230692.

The spelling of 71681861 in words is "seventy-one million, six hundred eighty-one thousand, eight hundred sixty-one".