129781449 has 18 divisors (see below), whose sum is σ = 218068890. Its totient is φ = 74160576.

The previous prime is 129781447. The next prime is 129781453. The reversal of 129781449 is 944187921.

It is a happy number.

129781449 is a `hidden beast` number, since 129 + 7 + 81 + 449 = 666.

It can be written as a sum of positive squares in only one way, i.e., 67765824 + 62015625 = 8232^2 + 7875^2 .

It is not a de Polignac number, because 129781449 - 2¹ = 129781447 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129781447) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 146704 + ... + 147585.

Almost surely, 2^129781449 is an apocalyptic number.

It is an amenable number.

129781449 is a deficient number, since it is larger than the sum of its proper divisors (88287441).

129781449 is a wasteful number, since it uses less digits than its factorization.

129781449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294309 (or 294299 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The square root of 129781449 is about 11392.1661241399. The cubic root of 129781449 is about 506.2956619079.

The spelling of 129781449 in words is "one hundred twenty-nine million, seven hundred eighty-one thousand, four hundred forty-nine".