129837438721 has 4 divisors (see below), whose sum is σ = 130496512212. Its totient is φ = 129178365232.

The previous prime is 129837438707. The next prime is 129837438739. The reversal of 129837438721 is 127834738921.

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

It can be written as a sum of positive squares in 2 ways, for example, as 61854177025 + 67983261696 = 248705^2 + 260736^2 .

It is a cyclic number.

It is not a de Polignac number, because 129837438721 - 2³¹ = 127689955073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129837438701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329536450 + ... + 329536843.

It is an arithmetic number, because the mean of its divisors is an integer number (32624128053).

Almost surely, 2^129837438721 is an apocalyptic number.

It is an amenable number.

129837438721 is a deficient number, since it is larger than the sum of its proper divisors (659073491).

129837438721 is an equidigital number, since it uses as much as digits as its factorization.

129837438721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659073490.

The product of its digits is 4064256, while the sum is 55.

The spelling of 129837438721 in words is "one hundred twenty-nine billion, eight hundred thirty-seven million, four hundred thirty-eight thousand, seven hundred twenty-one".