82216661 has 4 divisors (see below), whose sum is σ = 82740492. Its totient is φ = 81692832.

The previous prime is 82216657. The next prime is 82216691. The reversal of 82216661 is 16661228.

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 25816561 + 56400100 = 5081^2 + 7510^2 .

It is a cyclic number.

It is not a de Polignac number, because 82216661 - 2² = 82216657 is a prime.

It is a Duffinian number.

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 3 ways as a sum of consecutive naturals, for example, 261680 + ... + 261993.

It is an arithmetic number, because the mean of its divisors is an integer number (20685123).

Almost surely, 2^82216661 is an apocalyptic number.

It is an amenable number.

82216661 is a deficient number, since it is larger than the sum of its proper divisors (523831).

82216661 is a wasteful number, since it uses less digits than its factorization.

82216661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523830.

The product of its digits is 6912, while the sum is 32.

The square root of 82216661 is about 9067.3403487462. The cubic root of 82216661 is about 434.8304460969.

Adding to 82216661 its reverse (16661228), we get a palindrome (98877889).

The spelling of 82216661 in words is "eighty-two million, two hundred sixteen thousand, six hundred sixty-one".