81669061 has 4 divisors (see below), whose sum is σ = 81935392. Its totient is φ = 81402732.

The previous prime is 81669043. The next prime is 81669079. The reversal of 81669061 is 16096618.

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: 16096618 = 2 ⋅8048309.

It is an interprime number because it is at equal distance from previous prime (81669043) and next prime (81669079).

It is a cyclic number.

It is not a de Polignac number, because 81669061 - 2⁷ = 81668933 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81669061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81669361) 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, 132705 + ... + 133318.

It is an arithmetic number, because the mean of its divisors is an integer number (20483848).

Almost surely, 2^81669061 is an apocalyptic number.

It is an amenable number.

81669061 is a deficient number, since it is larger than the sum of its proper divisors (266331).

81669061 is a wasteful number, since it uses less digits than its factorization.

81669061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266330.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 81669061 is about 9037.0936146529. The cubic root of 81669061 is about 433.8629059366.

The spelling of 81669061 in words is "eighty-one million, six hundred sixty-nine thousand, sixty-one".