80221721 has 4 divisors (see below), whose sum is σ = 80449332. Its totient is φ = 79994112.

The previous prime is 80221717. The next prime is 80221753. The reversal of 80221721 is 12712208.

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

It can be written as a sum of positive squares in 2 ways, for example, as 44089600 + 36132121 = 6640^2 + 6011^2 .

It is a cyclic number.

It is not a de Polignac number, because 80221721 - 2² = 80221717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (80224721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113276 + ... + 113981.

It is an arithmetic number, because the mean of its divisors is an integer number (20112333).

Almost surely, 2^80221721 is an apocalyptic number.

It is an amenable number.

80221721 is a deficient number, since it is larger than the sum of its proper divisors (227611).

80221721 is a wasteful number, since it uses less digits than its factorization.

80221721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227610.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 80221721 is about 8956.6579146465. The cubic root of 80221721 is about 431.2846403316.

Adding to 80221721 its reverse (12712208), we get a palindrome (92933929).

The spelling of 80221721 in words is "eighty million, two hundred twenty-one thousand, seven hundred twenty-one".