83211721 has 8 divisors (see below), whose sum is σ = 84056000. Its totient is φ = 82371600.

The previous prime is 83211691. The next prime is 83211763. The reversal of 83211721 is 12711238.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-83211721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (83215721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51910 + ... + 53488.

It is an arithmetic number, because the mean of its divisors is an integer number (10507000).

Almost surely, 2^83211721 is an apocalyptic number.

It is an amenable number.

83211721 is a deficient number, since it is larger than the sum of its proper divisors (844279).

83211721 is a wasteful number, since it uses less digits than its factorization.

83211721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2079.

The product of its digits is 672, while the sum is 25.

The square root of 83211721 is about 9122.0458779815. The cubic root of 83211721 is about 436.5776526080.

Adding to 83211721 its reverse (12711238), we get a palindrome (95922959).

The spelling of 83211721 in words is "eighty-three million, two hundred eleven thousand, seven hundred twenty-one".