129856918 has 4 divisors (see below), whose sum is σ = 194785380. Its totient is φ = 64928458.

The previous prime is 129856913. The next prime is 129856973. The reversal of 129856918 is 819658921.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129856913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32464228 + ... + 32464231.

It is an arithmetic number, because the mean of its divisors is an integer number (48696345).

Almost surely, 2^129856918 is an apocalyptic number.

129856918 is a deficient number, since it is larger than the sum of its proper divisors (64928462).

129856918 is an equidigital number, since it uses as much as digits as its factorization.

129856918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64928461.

The product of its digits is 311040, while the sum is 49.

The square root of 129856918 is about 11395.4779627710. The cubic root of 129856918 is about 506.3937812811.

The spelling of 129856918 in words is "one hundred twenty-nine million, eight hundred fifty-six thousand, nine hundred eighteen".