81628469 has 8 divisors (see below), whose sum is σ = 87987480. Its totient is φ = 75280896.

The previous prime is 81628457. The next prime is 81628513. The reversal of 81628469 is 96482618.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5712100 + 75916369 = 2390^2 + 8713^2 .

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 81628469 - 2⁸ = 81628213 is a prime.

It is a super-2 number, since 2×81628469² = 13326413902567922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81628429) 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, 17249 + ... + 21465.

It is an arithmetic number, because the mean of its divisors is an integer number (10998435).

Almost surely, 2^81628469 is an apocalyptic number.

It is an amenable number.

81628469 is a deficient number, since it is larger than the sum of its proper divisors (6359011).

81628469 is a wasteful number, since it uses less digits than its factorization.

81628469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5719.

The product of its digits is 165888, while the sum is 44.

The square root of 81628469 is about 9034.8474807271. The cubic root of 81628469 is about 433.7910130171.

The spelling of 81628469 in words is "eighty-one million, six hundred twenty-eight thousand, four hundred sixty-nine".