80021666 has 4 divisors (see below), whose sum is σ = 120032502. Its totient is φ = 40010832.

The previous prime is 80021657. The next prime is 80021671. The reversal of 80021666 is 66612008.

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., 46717225 + 33304441 = 6835^2 + 5771^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20005415 + ... + 20005418.

Almost surely, 2^80021666 is an apocalyptic number.

80021666 is a deficient number, since it is larger than the sum of its proper divisors (40010836).

80021666 is a wasteful number, since it uses less digits than its factorization.

80021666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40010835.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 80021666 is about 8945.4829942268. The cubic root of 80021666 is about 430.9258328137.

The spelling of 80021666 in words is "eighty million, twenty-one thousand, six hundred sixty-six".