73431440640 has 432 divisors, whose sum is σ = 261172574208. Its totient is φ = 19040845824.

The previous prime is 73431440611. The next prime is 73431440657. The reversal of 73431440640 is 4604413437.

73431440640 is a `hidden beast` number, since 7 + 3 + 4 + 3 + 1 + 4 + 4 + 0 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 73431440595 and 73431440604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77540647 + ... + 77541593.

It is an arithmetic number, because the mean of its divisors is an integer number (604566144).

Almost surely, 2^73431440640 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 73431440640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130586287104).

73431440640 is an abundant number, since it is smaller than the sum of its proper divisors (187741133568).

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

73431440640 is a wasteful number, since it uses less digits than its factorization.

73431440640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1154 (or 1137 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 36.

The spelling of 73431440640 in words is "seventy-three billion, four hundred thirty-one million, four hundred forty thousand, six hundred forty".