129278640 has 80 divisors (see below), whose sum is σ = 410116608. Its totient is φ = 33669888.

The previous prime is 129278579. The next prime is 129278647. The reversal of 129278640 is 46872921.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (129278647) 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 15 ways as a sum of consecutive naturals, for example, 4057 + ... + 16583.

Almost surely, 2^129278640 is an apocalyptic number.

129278640 is a gapful number since it is divisible by the number (10) 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 129278640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (205058304).

129278640 is an abundant number, since it is smaller than the sum of its proper divisors (280837968).

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

129278640 is a wasteful number, since it uses less digits than its factorization.

129278640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12586 (or 12580 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 129278640 is about 11370.0765168929. The cubic root of 129278640 is about 505.6409728519.

The spelling of 129278640 in words is "one hundred twenty-nine million, two hundred seventy-eight thousand, six hundred forty".