129920026 has 4 divisors (see below), whose sum is σ = 194880042. Its totient is φ = 64960012.

The previous prime is 129920017. The next prime is 129920027. The reversal of 129920026 is 620029921.

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., 82791801 + 47128225 = 9099^2 + 6865^2 .

It is a super-3 number, since 3×129920026³ (a number of 25 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (31) 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 129920026.

It is not an unprimeable number, because it can be changed into a prime (129920027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32480005 + ... + 32480008.

Almost surely, 2^129920026 is an apocalyptic number.

129920026 is a deficient number, since it is larger than the sum of its proper divisors (64960016).

129920026 is an equidigital number, since it uses as much as digits as its factorization.

129920026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64960015.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 129920026 is about 11398.2466195464. The cubic root of 129920026 is about 506.4758005880.

Adding to 129920026 its reverse (620029921), we get a palindrome (749949947).

The spelling of 129920026 in words is "one hundred twenty-nine million, nine hundred twenty thousand, twenty-six".