81669673 has 8 divisors (see below), whose sum is σ = 82811592. Its totient is φ = 80535936.

The previous prime is 81669641. The next prime is 81669689. The reversal of 81669673 is 37696618.

It can be written as a sum of positive squares in 4 ways, for example, as 2304 + 81667369 = 48^2 + 9037^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81669673 - 2⁵ = 81669641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81669613) 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, 19611 + ... + 23407.

It is an arithmetic number, because the mean of its divisors is an integer number (10351449).

Almost surely, 2^81669673 is an apocalyptic number.

It is an amenable number.

81669673 is a deficient number, since it is larger than the sum of its proper divisors (1141919).

81669673 is a wasteful number, since it uses less digits than its factorization.

81669673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4091.

The product of its digits is 326592, while the sum is 46.

The square root of 81669673 is about 9037.1274750332. The cubic root of 81669673 is about 433.8639896739.

The spelling of 81669673 in words is "eighty-one million, six hundred sixty-nine thousand, six hundred seventy-three".