82105561 has 6 divisors (see below), whose sum is σ = 85831130. Its totient is φ = 78535248.

The previous prime is 82105559. The next prime is 82105571. The reversal of 82105561 is 16550128.

It can be written as a sum of positive squares in only one way, i.e., 42968025 + 39137536 = 6555^2 + 6256^2 .

It is not a de Polignac number, because 82105561 - 2¹ = 82105559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82105501) 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, 77076 + ... + 78133.

Almost surely, 2^82105561 is an apocalyptic number.

It is an amenable number.

82105561 is a deficient number, since it is larger than the sum of its proper divisors (3725569).

82105561 is a wasteful number, since it uses less digits than its factorization.

82105561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155255 (or 155232 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 82105561 is about 9061.2118946640. The cubic root of 82105561 is about 434.6344945759.

Adding to 82105561 its reverse (16550128), we get a palindrome (98655689).

The spelling of 82105561 in words is "eighty-two million, one hundred five thousand, five hundred sixty-one".