129139840 has 32 divisors (see below), whose sum is σ = 308726460. Its totient is φ = 51655680.

The previous prime is 129139819. The next prime is 129139877. The reversal of 129139840 is 48931921.

It can be written as a sum of positive squares in 2 ways, for example, as 116122176 + 13017664 = 10776^2 + 3608^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 129139840.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100251 + ... + 101530.

Almost surely, 2^129139840 is an apocalyptic number.

129139840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129139840 is an abundant number, since it is smaller than the sum of its proper divisors (179586620).

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

129139840 is an equidigital number, since it uses as much as digits as its factorization.

129139840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201800 (or 201788 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 129139840 is about 11363.9711368870. The cubic root of 129139840 is about 505.4599475891.

The spelling of 129139840 in words is "one hundred twenty-nine million, one hundred thirty-nine thousand, eight hundred forty".