81269189 has 4 divisors (see below), whose sum is σ = 84802656. Its totient is φ = 77735724.

The previous prime is 81269179. The next prime is 81269203. The reversal of 81269189 is 98196218.

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 81269189 - 2¹⁶ = 81203653 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81269159) 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, 1766699 + ... + 1766744.

It is an arithmetic number, because the mean of its divisors is an integer number (21200664).

Almost surely, 2^81269189 is an apocalyptic number.

It is an amenable number.

81269189 is a deficient number, since it is larger than the sum of its proper divisors (3533467).

81269189 is a wasteful number, since it uses less digits than its factorization.

81269189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3533466.

The product of its digits is 62208, while the sum is 44.

The square root of 81269189 is about 9014.9425400276. The cubic root of 81269189 is about 433.1536469346.

The spelling of 81269189 in words is "eighty-one million, two hundred sixty-nine thousand, one hundred eighty-nine".