71990666 has 8 divisors (see below), whose sum is σ = 117802944. Its totient is φ = 32723020.

The previous prime is 71990651. The next prime is 71990669. The reversal of 71990666 is 66609917.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×71990666² = 10365311982247112, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (71990669) 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 in 3 ways as a sum of consecutive naturals, for example, 1636130 + ... + 1636173.

It is an arithmetic number, because the mean of its divisors is an integer number (14725368).

Almost surely, 2^71990666 is an apocalyptic number.

71990666 is a deficient number, since it is larger than the sum of its proper divisors (45812278).

71990666 is a wasteful number, since it uses less digits than its factorization.

71990666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3272316.

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 71990666 is about 8484.7313451871. The cubic root of 71990666 is about 415.9987865164.

The spelling of 71990666 in words is "seventy-one million, nine hundred ninety thousand, six hundred sixty-six".