82216621 has 6 divisors (see below), whose sum is σ = 83800010. Its totient is φ = 80662608.

The previous prime is 82216601. The next prime is 82216633. The reversal of 82216621 is 12661228.

It can be written as a sum of positive squares in 3 ways, for example, as 33062500 + 49154121 = 5750^2 + 7011^2 .

It is a de Polignac number, because none of the positive numbers 2^k-82216621 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 82216621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82216601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11826 + ... + 17443.

Almost surely, 2^82216621 is an apocalyptic number.

It is an amenable number.

82216621 is a deficient number, since it is larger than the sum of its proper divisors (1583389).

82216621 is an equidigital number, since it uses as much as digits as its factorization.

82216621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29375 (or 29322 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 82216621 is about 9067.3381430274. The cubic root of 82216621 is about 434.8303755791.

Adding to 82216621 its reverse (12661228), we get a palindrome (94877849).

The spelling of 82216621 in words is "eighty-two million, two hundred sixteen thousand, six hundred twenty-one".