129943978 has 8 divisors (see below), whose sum is σ = 195605568. Its totient is φ = 64742124.

The previous prime is 129943949. The next prime is 129943991. The reversal of 129943978 is 879349921.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 114226 + ... + 115357.

It is an arithmetic number, because the mean of its divisors is an integer number (24450696).

Almost surely, 2^129943978 is an apocalyptic number.

129943978 is a deficient number, since it is larger than the sum of its proper divisors (65661590).

129943978 is a wasteful number, since it uses less digits than its factorization.

129943978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229868.

The product of its digits is 979776, while the sum is 52.

The square root of 129943978 is about 11399.2972590419. The cubic root of 129943978 is about 506.5069232289.

The spelling of 129943978 in words is "one hundred twenty-nine million, nine hundred forty-three thousand, nine hundred seventy-eight".