129749220 has 36 divisors (see below), whose sum is σ = 393573180. Its totient is φ = 34599744.

The previous prime is 129749197. The next prime is 129749231. The reversal of 129749220 is 22947921.

It can be written as a sum of positive squares in 2 ways, for example, as 60093504 + 69655716 = 7752^2 + 8346^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 360235 + ... + 360594.

Almost surely, 2^129749220 is an apocalyptic number.

129749220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129749220 is an abundant number, since it is smaller than the sum of its proper divisors (263823960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

129749220 is a wasteful number, since it uses less digits than its factorization.

129749220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720844 (or 720839 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 129749220 is about 11390.7515116431. The cubic root of 129749220 is about 506.2537484862.

The spelling of 129749220 in words is "one hundred twenty-nine million, seven hundred forty-nine thousand, two hundred twenty".