81693923040 has 576 divisors, whose sum is σ = 308080281600. Its totient is φ = 19632844800.

The previous prime is 81693922993. The next prime is 81693923053. The reversal of 81693923040 is 4032939618.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 51736971 + ... + 51738549.

It is an arithmetic number, because the mean of its divisors is an integer number (534861600).

Almost surely, 2^81693923040 is an apocalyptic number.

81693923040 is a gapful number since it is divisible by the number (80) 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 81693923040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154040140800).

81693923040 is an abundant number, since it is smaller than the sum of its proper divisors (226386358560).

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

81693923040 is a wasteful number, since it uses less digits than its factorization.

81693923040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1711 (or 1700 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The spelling of 81693923040 in words is "eighty-one billion, six hundred ninety-three million, nine hundred twenty-three thousand, forty".