129697978 has 4 divisors (see below), whose sum is σ = 194546970. Its totient is φ = 64848988.

The previous prime is 129697963. The next prime is 129697979. The reversal of 129697978 is 879796921.

It is a happy number.

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., 121154049 + 8543929 = 11007^2 + 2923^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (129697979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32424493 + ... + 32424496.

Almost surely, 2^129697978 is an apocalyptic number.

129697978 is a deficient number, since it is larger than the sum of its proper divisors (64848992).

129697978 is an equidigital number, since it uses as much as digits as its factorization.

129697978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64848991.

The product of its digits is 3429216, while the sum is 58.

The square root of 129697978 is about 11388.5020086050. The cubic root of 129697978 is about 506.1870945971.

The spelling of 129697978 in words is "one hundred twenty-nine million, six hundred ninety-seven thousand, nine hundred seventy-eight".