71661377 has 2 divisors, whose sum is σ = 71661378. Its totient is φ = 71661376.

The previous prime is 71661371. The next prime is 71661379. The reversal of 71661377 is 77316617.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70492816 + 1168561 = 8396^2 + 1081^2 .

It is a cyclic number.

It is not a de Polignac number, because 71661377 - 2⁴ = 71661361 is a prime.

It is a super-2 number, since 2×71661377² = 10270705907072258, which contains 22 as substring.

Together with 71661379, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71661377.

It is not a weakly prime, because it can be changed into another prime (71661371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35830688 + 35830689.

It is an arithmetic number, because the mean of its divisors is an integer number (35830689).

Almost surely, 2^71661377 is an apocalyptic number.

It is an amenable number.

71661377 is a deficient number, since it is larger than the sum of its proper divisors (1).

71661377 is an equidigital number, since it uses as much as digits as its factorization.

71661377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37044, while the sum is 38.

The square root of 71661377 is about 8465.3043064027. The cubic root of 71661377 is about 415.3635503976.

The spelling of 71661377 in words is "seventy-one million, six hundred sixty-one thousand, three hundred seventy-seven".