129400320 has 320 divisors, whose sum is σ = 494968320. Its totient is φ = 28213248.

The previous prime is 129400307. The next prime is 129400333. The reversal of 129400320 is 23004921.

It is an interprime number because it is at equal distance from previous prime (129400307) and next prime (129400333).

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×129400320² = 33488885632204800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1558999 + ... + 1559081.

It is an arithmetic number, because the mean of its divisors is an integer number (1546776).

Almost surely, 2^129400320 is an apocalyptic number.

129400320 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 129400320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247484160).

129400320 is an abundant number, since it is smaller than the sum of its proper divisors (365568000).

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

129400320 is an equidigital number, since it uses as much as digits as its factorization.

129400320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 129400320 is about 11375.4261458637. The cubic root of 129400320 is about 505.7995633721.

The spelling of 129400320 in words is "one hundred twenty-nine million, four hundred thousand, three hundred twenty".