129869820 has 36 divisors (see below), whose sum is σ = 393939000. Its totient is φ = 34631904.

The previous prime is 129869813. The next prime is 129869821. The reversal of 129869820 is 28968921.

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 (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129869821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 360570 + ... + 360929.

It is an arithmetic number, because the mean of its divisors is an integer number (10942750).

Almost surely, 2^129869820 is an apocalyptic number.

129869820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129869820 is an abundant number, since it is smaller than the sum of its proper divisors (264069180).

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

129869820 is a wasteful number, since it uses less digits than its factorization.

129869820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721514 (or 721509 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 129869820 is about 11396.0440504589. The cubic root of 129869820 is about 506.4105517294.

The spelling of 129869820 in words is "one hundred twenty-nine million, eight hundred sixty-nine thousand, eight hundred twenty".