81929169504 has 864 divisors, whose sum is σ = 315960765120. Its totient is φ = 19582746624.

The previous prime is 81929169499. The next prime is 81929169541. The reversal of 81929169504 is 40596192918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 219649062 + ... + 219649434.

It is an arithmetic number, because the mean of its divisors is an integer number (365695330).

Almost surely, 2^81929169504 is an apocalyptic number.

81929169504 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81929169504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157980382560).

81929169504 is an abundant number, since it is smaller than the sum of its proper divisors (234031595616).

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

81929169504 is a wasteful number, since it uses less digits than its factorization.

81929169504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472 (or 444 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 54.

The spelling of 81929169504 in words is "eighty-one billion, nine hundred twenty-nine million, one hundred sixty-nine thousand, five hundred four".