83216621 has 4 divisors (see below), whose sum is σ = 83479452. Its totient is φ = 82953792.

The previous prime is 83216603. The next prime is 83216629. The reversal of 83216621 is 12661238.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12661238 = 2 ⋅6330619.

It can be written as a sum of positive squares in 2 ways, for example, as 28249225 + 54967396 = 5315^2 + 7414^2 .

It is a cyclic number.

It is not a de Polignac number, because 83216621 - 2⁶ = 83216557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83216629) 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, 130940 + ... + 131573.

It is an arithmetic number, because the mean of its divisors is an integer number (20869863).

Almost surely, 2^83216621 is an apocalyptic number.

It is an amenable number.

83216621 is a deficient number, since it is larger than the sum of its proper divisors (262831).

83216621 is a wasteful number, since it uses less digits than its factorization.

83216621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262830.

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

The square root of 83216621 is about 9122.3144541284. The cubic root of 83216621 is about 436.5862218675.

Adding to 83216621 its reverse (12661238), we get a palindrome (95877859).

The spelling of 83216621 in words is "eighty-three million, two hundred sixteen thousand, six hundred twenty-one".