81982289 has 4 divisors (see below), whose sum is σ = 82608240. Its totient is φ = 81356340.

The previous prime is 81982273. The next prime is 81982301. The reversal of 81982289 is 98228918.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98228918 = 2 ⋅49114459.

It is a cyclic number.

It is not a de Polignac number, because 81982289 - 2⁴ = 81982273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81982249) 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, 312779 + ... + 313040.

It is an arithmetic number, because the mean of its divisors is an integer number (20652060).

Almost surely, 2^81982289 is an apocalyptic number.

It is an amenable number.

81982289 is a deficient number, since it is larger than the sum of its proper divisors (625951).

81982289 is a wasteful number, since it uses less digits than its factorization.

81982289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625950.

The product of its digits is 165888, while the sum is 47.

The square root of 81982289 is about 9054.4071589475. The cubic root of 81982289 is about 434.4168678240.

The spelling of 81982289 in words is "eighty-one million, nine hundred eighty-two thousand, two hundred eighty-nine".