81669289 has 8 divisors (see below), whose sum is σ = 88106312. Its totient is φ = 75254400.

The previous prime is 81669257. The next prime is 81669293. The reversal of 81669289 is 98296618.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 34609689 + 47059600 = 5883^2 + 6860^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81669289 - 2⁵ = 81669257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81669209) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2587 + ... + 13039.

It is an arithmetic number, because the mean of its divisors is an integer number (11013289).

Almost surely, 2^81669289 is an apocalyptic number.

It is an amenable number.

81669289 is a deficient number, since it is larger than the sum of its proper divisors (6437023).

81669289 is a wasteful number, since it uses less digits than its factorization.

81669289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11067.

The product of its digits is 373248, while the sum is 49.

The square root of 81669289 is about 9037.1062293192. The cubic root of 81669289 is about 433.8633096825.

The spelling of 81669289 in words is "eighty-one million, six hundred sixty-nine thousand, two hundred eighty-nine".