129420778 has 4 divisors (see below), whose sum is σ = 194131170. Its totient is φ = 64710388.

The previous prime is 129420727. The next prime is 129420803. The reversal of 129420778 is 877024921.

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

It can be written as a sum of positive squares in only one way, i.e., 83411689 + 46009089 = 9133^2 + 6783^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 129420778.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32355193 + ... + 32355196.

Almost surely, 2^129420778 is an apocalyptic number.

129420778 is a deficient number, since it is larger than the sum of its proper divisors (64710392).

129420778 is an equidigital number, since it uses as much as digits as its factorization.

129420778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64710391.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 129420778 is about 11376.3253293847. The cubic root of 129420778 is about 505.8262173562.

The spelling of 129420778 in words is "one hundred twenty-nine million, four hundred twenty thousand, seven hundred seventy-eight".