129678725 has 36 divisors (see below), whose sum is σ = 178509408. Its totient is φ = 93376800.

The previous prime is 129678707. The next prime is 129678727. The reversal of 129678725 is 527876921.

It is a happy number.

It is not a de Polignac number, because 129678725 - 2¹⁰ = 129677701 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 129678725.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129678727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 492944 + ... + 493206.

Almost surely, 2^129678725 is an apocalyptic number.

129678725 is the 6575-th octagonal number.

It is an amenable number.

129678725 is a deficient number, since it is larger than the sum of its proper divisors (48830683).

129678725 is a wasteful number, since it uses less digits than its factorization.

129678725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458 (or 442 counting only the distinct ones).

The product of its digits is 423360, while the sum is 47.

The square root of 129678725 is about 11387.6566948604. The cubic root of 129678725 is about 506.1620463978.

The spelling of 129678725 in words is "one hundred twenty-nine million, six hundred seventy-eight thousand, seven hundred twenty-five".