73217021 has 8 divisors (see below), whose sum is σ = 75749688. Its totient is φ = 70720000.

The previous prime is 73217017. The next prime is 73217033. The reversal of 73217021 is 12071237.

It can be written as a sum of positive squares in 4 ways, for example, as 5812921 + 67404100 = 2411^2 + 8210^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 73217021 - 2² = 73217017 is a prime.

It is a super-2 number, since 2×73217021² = 10721464328228882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73214021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4700 + ... + 12981.

It is an arithmetic number, because the mean of its divisors is an integer number (9468711).

Almost surely, 2^73217021 is an apocalyptic number.

It is an amenable number.

73217021 is a deficient number, since it is larger than the sum of its proper divisors (2532667).

73217021 is a wasteful number, since it uses less digits than its factorization.

73217021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17823.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 73217021 is about 8556.6945136542. The cubic root of 73217021 is about 418.3476671473.

Adding to 73217021 its reverse (12071237), we get a palindrome (85288258).

The spelling of 73217021 in words is "seventy-three million, two hundred seventeen thousand, twenty-one".