31729840128 has 416 divisors, whose sum is σ = 113798545920. Its totient is φ = 8528855040.

The previous prime is 31729840127. The next prime is 31729840157. The reversal of 31729840128 is 82104892713.

It is a happy number.

31729840128 is a `hidden beast` number, since 317 + 298 + 40 + 1 + 2 + 8 = 666.

It is a super-3 number, since 3×31729840128³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31729840123) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13159243 + ... + 13161653.

Almost surely, 2^31729840128 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 31729840128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56899272960).

31729840128 is an abundant number, since it is smaller than the sum of its proper divisors (82068705792).

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

31729840128 is a wasteful number, since it uses less digits than its factorization.

31729840128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2468 (or 2440 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 31729840128 in words is "thirty-one billion, seven hundred twenty-nine million, eight hundred forty thousand, one hundred twenty-eight".