71681866 has 4 divisors (see below), whose sum is σ = 107522802. Its totient is φ = 35840932.

The previous prime is 71681861. The next prime is 71681867. The reversal of 71681866 is 66818617.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 57836025 + 13845841 = 7605^2 + 3721^2 .

It is not an unprimeable number, because it can be changed into a prime (71681861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17920465 + ... + 17920468.

Almost surely, 2^71681866 is an apocalyptic number.

71681866 is a deficient number, since it is larger than the sum of its proper divisors (35840936).

71681866 is a wasteful number, since it uses less digits than its factorization.

71681866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35840935.

The product of its digits is 96768, while the sum is 43.

The square root of 71681866 is about 8466.5143949562. The cubic root of 71681866 is about 415.4031327277.

The spelling of 71681866 in words is "seventy-one million, six hundred eighty-one thousand, eight hundred sixty-six".