129668728 has 32 divisors (see below), whose sum is σ = 280994400. Its totient is φ = 54945792.

The previous prime is 129668717. The next prime is 129668729. The reversal of 129668728 is 827866921.

It is a super-2 number, since 2×129668728² = 33627958042275968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129668729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8025 + ... + 17992.

It is an arithmetic number, because the mean of its divisors is an integer number (8781075).

Almost surely, 2^129668728 is an apocalyptic number.

It is an amenable number.

129668728 is an abundant number, since it is smaller than the sum of its proper divisors (151325672).

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

129668728 is a wasteful number, since it uses less digits than its factorization.

129668728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26119 (or 26115 counting only the distinct ones).

The product of its digits is 580608, while the sum is 49.

The square root of 129668728 is about 11387.2177462276. The cubic root of 129668728 is about 506.1490392989.

The spelling of 129668728 in words is "one hundred twenty-nine million, six hundred sixty-eight thousand, seven hundred twenty-eight".