129972394 has 4 divisors (see below), whose sum is σ = 194958594. Its totient is φ = 64986196.

The previous prime is 129972391. The next prime is 129972421. The reversal of 129972394 is 493279921.

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., 127396369 + 2576025 = 11287^2 + 1605^2 .

It is not an unprimeable number, because it can be changed into a prime (129972391) by changing a digit.

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 as a sum of consecutive naturals, namely, 32493097 + ... + 32493100.

Almost surely, 2^129972394 is an apocalyptic number.

129972394 is a deficient number, since it is larger than the sum of its proper divisors (64986200).

129972394 is an equidigital number, since it uses as much as digits as its factorization.

129972394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64986199.

The product of its digits is 244944, while the sum is 46.

The square root of 129972394 is about 11400.5435835314. The cubic root of 129972394 is about 506.5438413222.

The spelling of 129972394 in words is "one hundred twenty-nine million, nine hundred seventy-two thousand, three hundred ninety-four".