82978561 has 4 divisors (see below), whose sum is σ = 82996992. Its totient is φ = 82960132.

The previous prime is 82978559. The next prime is 82978601. The reversal of 82978561 is 16587928.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 82978561 - 2¹ = 82978559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82978501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2520 + ... + 13126.

It is an arithmetic number, because the mean of its divisors is an integer number (20749248).

Almost surely, 2^82978561 is an apocalyptic number.

It is an amenable number.

82978561 is a deficient number, since it is larger than the sum of its proper divisors (18431).

82978561 is a wasteful number, since it uses less digits than its factorization.

82978561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18430.

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

The square root of 82978561 is about 9109.2568851691. The cubic root of 82978561 is about 436.1695063076.

The spelling of 82978561 in words is "eighty-two million, nine hundred seventy-eight thousand, five hundred sixty-one".