129221040 has 160 divisors (see below), whose sum is σ = 437472000. Its totient is φ = 31362048.

The previous prime is 129221039. The next prime is 129221041. The reversal of 129221040 is 40122921.

It is an interprime number because it is at equal distance from previous prime (129221039) and next prime (129221041).

It is a junction number, because it is equal to n+sod(n) for n = 129220998 and 129221016.

It is not an unprimeable number, because it can be changed into a prime (129221041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 258711 + ... + 259209.

It is an arithmetic number, because the mean of its divisors is an integer number (2734200).

Almost surely, 2^129221040 is an apocalyptic number.

129221040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 129221040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218736000).

129221040 is an abundant number, since it is smaller than the sum of its proper divisors (308250960).

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

129221040 is a wasteful number, since it uses less digits than its factorization.

129221040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611 (or 605 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 129221040 is about 11367.5432702057. The cubic root of 129221040 is about 505.5658657122.

Adding to 129221040 its reverse (40122921), we get a palindrome (169343961).

The spelling of 129221040 in words is "one hundred twenty-nine million, two hundred twenty-one thousand, forty".