81603757408 has 96 divisors (see below), whose sum is σ = 173720163456. Its totient is φ = 37589680128.

The previous prime is 81603757399. The next prime is 81603757429. The reversal of 81603757408 is 80475730618.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13346160 + ... + 13352272.

It is an arithmetic number, because the mean of its divisors is an integer number (1809585036).

Almost surely, 2^81603757408 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 81603757408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86860081728).

81603757408 is an abundant number, since it is smaller than the sum of its proper divisors (92116406048).

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

81603757408 is a wasteful number, since it uses less digits than its factorization.

81603757408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6656 (or 6648 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 49.

The spelling of 81603757408 in words is "eighty-one billion, six hundred three million, seven hundred fifty-seven thousand, four hundred eight".