81626 has 4 divisors (see below), whose sum is σ = 122442. Its totient is φ = 40812.

The previous prime is 81619. The next prime is 81629. The reversal of 81626 is 62618.

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., 42025 + 39601 = 205^2 + 199^2 .

It is not an unprimeable number, because it can be changed into a prime (81629) 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 as a sum of consecutive naturals, namely, 20405 + ... + 20408.

2⁸¹⁶²⁶ is an apocalyptic number.

81626 is a deficient number, since it is larger than the sum of its proper divisors (40816).

81626 is a wasteful number, since it uses less digits than its factorization.

81626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40815.

The product of its digits is 576, while the sum is 23.

The square root of 81626 is about 285.7026426199. The cubic root of 81626 is about 43.3786639376.

It can be divided in two parts, 81 and 626, that added together give a palindrome (707).

The spelling of 81626 in words is "eighty-one thousand, six hundred twenty-six".