129621381 has 8 divisors (see below), whose sum is σ = 173185344. Its totient is φ = 86235840.

The previous prime is 129621367. The next prime is 129621389. The reversal of 129621381 is 183126921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 129621381 - 2¹⁰ = 129620357 is a prime.

It is a super-2 number, since 2×129621381² = 33603404824694322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129621389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42900 + ... + 45821.

It is an arithmetic number, because the mean of its divisors is an integer number (21648168).

Almost surely, 2^129621381 is an apocalyptic number.

It is an amenable number.

129621381 is a deficient number, since it is larger than the sum of its proper divisors (43563963).

129621381 is an equidigital number, since it uses as much as digits as its factorization.

129621381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89211.

The product of its digits is 5184, while the sum is 33.

The square root of 129621381 is about 11385.1386025819. The cubic root of 129621381 is about 506.0874270240.

The spelling of 129621381 in words is "one hundred twenty-nine million, six hundred twenty-one thousand, three hundred eighty-one".