71771957 has 2 divisors, whose sum is σ = 71771958. Its totient is φ = 71771956.

The previous prime is 71771933. The next prime is 71771963. The reversal of 71771957 is 75917717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50112241 + 21659716 = 7079^2 + 4654^2 .

It is an emirp because it is prime and its reverse (75917717) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71771957 - 2⁶ = 71771893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71771057) 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, 35885978 + 35885979.

It is an arithmetic number, because the mean of its divisors is an integer number (35885979).

Almost surely, 2^71771957 is an apocalyptic number.

It is an amenable number.

71771957 is a deficient number, since it is larger than the sum of its proper divisors (1).

71771957 is an equidigital number, since it uses as much as digits as its factorization.

71771957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108045, while the sum is 44.

The square root of 71771957 is about 8471.8331546366. The cubic root of 71771957 is about 415.5770884678.

Subtracting 71771957 from its reverse (75917717), we obtain a triangular number (4145760 = T₂₈₇₉).

The spelling of 71771957 in words is "seventy-one million, seven hundred seventy-one thousand, nine hundred fifty-seven".