129747747921 has 16 divisors (see below), whose sum is σ = 191817835968. Its totient is φ = 77345899200.

The previous prime is 129747747887. The next prime is 129747747947.

129747747921 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 129747747921 - 2⁷ = 129747747793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129747747721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32225446 + ... + 32229471.

It is an arithmetic number, because the mean of its divisors is an integer number (11988614748).

Almost surely, 2^129747747921 is an apocalyptic number.

129747747921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129747747921 is a deficient number, since it is larger than the sum of its proper divisors (62070088047).

129747747921 is a wasteful number, since it uses less digits than its factorization.

129747747921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64454992.

The product of its digits is 12446784, while the sum is 60.

The spelling of 129747747921 in words is "one hundred twenty-nine billion, seven hundred forty-seven million, seven hundred forty-seven thousand, nine hundred twenty-one".