82987561 has 4 divisors (see below), whose sum is σ = 83006212. Its totient is φ = 82968912.

The previous prime is 82987547. The next prime is 82987601. The reversal of 82987561 is 16578928.

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 37896336 + 45091225 = 6156^2 + 6715^2 .

It is a cyclic number.

It is not a de Polignac number, because 82987561 - 2⁵ = 82987529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82987061) 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, 1675 + ... + 12991.

It is an arithmetic number, because the mean of its divisors is an integer number (20751553).

Almost surely, 2^82987561 is an apocalyptic number.

It is an amenable number.

82987561 is a deficient number, since it is larger than the sum of its proper divisors (18651).

82987561 is a wasteful number, since it uses less digits than its factorization.

82987561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18650.

The product of its digits is 241920, while the sum is 46.

The square root of 82987561 is about 9109.7508747495. The cubic root of 82987561 is about 436.1852749736.

The spelling of 82987561 in words is "eighty-two million, nine hundred eighty-seven thousand, five hundred sixty-one".