81593730672 has 120 divisors (see below), whose sum is σ = 229375079472. Its totient is φ = 24973516800.

The previous prime is 81593730649. The next prime is 81593730677. The reversal of 81593730672 is 27603739518.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81593730677) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 497022 + ... + 640482.

Almost surely, 2^81593730672 is an apocalyptic number.

81593730672 is a gapful number since it is divisible by the number (82) 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 81593730672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114687539736).

81593730672 is an abundant number, since it is smaller than the sum of its proper divisors (147781348800).

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

81593730672 is a wasteful number, since it uses less digits than its factorization.

81593730672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143547 (or 143524 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 51.

The spelling of 81593730672 in words is "eighty-one billion, five hundred ninety-three million, seven hundred thirty thousand, six hundred seventy-two".