81689834 has 4 divisors (see below), whose sum is σ = 122534754. Its totient is φ = 40844916.

The previous prime is 81689827. The next prime is 81689837. The reversal of 81689834 is 43898618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 40921609 + 40768225 = 6397^2 + 6385^2 .

It is not an unprimeable number, because it can be changed into a prime (81689837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20422457 + ... + 20422460.

Almost surely, 2^81689834 is an apocalyptic number.

81689834 is a deficient number, since it is larger than the sum of its proper divisors (40844920).

81689834 is a wasteful number, since it uses less digits than its factorization.

81689834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40844919.

The product of its digits is 331776, while the sum is 47.

The square root of 81689834 is about 9038.2428602024. The cubic root of 81689834 is about 433.8996880015.

The spelling of 81689834 in words is "eighty-one million, six hundred eighty-nine thousand, eight hundred thirty-four".