129117840 has 40 divisors (see below), whose sum is σ = 400266048. Its totient is φ = 34431360.

The previous prime is 129117817. The next prime is 129117847. The reversal of 129117840 is 48711921.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (129117847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 268756 + ... + 269235.

Almost surely, 2^129117840 is an apocalyptic number.

129117840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129117840 is an abundant number, since it is smaller than the sum of its proper divisors (271148208).

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

129117840 is a wasteful number, since it uses less digits than its factorization.

129117840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538007 (or 538001 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 129117840 is about 11363.0031241745. The cubic root of 129117840 is about 505.4312429168.

The spelling of 129117840 in words is "one hundred twenty-nine million, one hundred seventeen thousand, eight hundred forty".