129213771 has 4 divisors (see below), whose sum is σ = 172285032. Its totient is φ = 86142512.

The previous prime is 129213769. The next prime is 129213779. The reversal of 129213771 is 177312921.

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

It is a cyclic number.

It is not a de Polignac number, because 129213771 - 2¹ = 129213769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129213779) 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, 21535626 + ... + 21535631.

It is an arithmetic number, because the mean of its divisors is an integer number (43071258).

Almost surely, 2^129213771 is an apocalyptic number.

129213771 is a deficient number, since it is larger than the sum of its proper divisors (43071261).

129213771 is an equidigital number, since it uses as much as digits as its factorization.

129213771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43071260.

The product of its digits is 5292, while the sum is 33.

The square root of 129213771 is about 11367.2235396336. The cubic root of 129213771 is about 505.5563857617.

The spelling of 129213771 in words is "one hundred twenty-nine million, two hundred thirteen thousand, seven hundred seventy-one".