81769408 has 56 divisors (see below), whose sum is σ = 190491872. Its totient is φ = 34089984.

The previous prime is 81769403. The next prime is 81769421. The reversal of 81769408 is 80496718.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81769403) 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, 14110 + ... + 19042.

Almost surely, 2^81769408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81769408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95245936).

81769408 is an abundant number, since it is smaller than the sum of its proper divisors (108722464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81769408 is a wasteful number, since it uses less digits than its factorization.

81769408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4989 (or 4979 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 81769408 is about 9042.6438611725. The cubic root of 81769408 is about 434.0405293898.

It can be divided in two parts, 817 and 69408, that added together give a square (70225 = 265²).

The spelling of 81769408 in words is "eighty-one million, seven hundred sixty-nine thousand, four hundred eight".