129819821 has 8 divisors (see below), whose sum is σ = 131164704. Its totient is φ = 128480560.

The previous prime is 129819793. The next prime is 129819841. The reversal of 129819821 is 128918921.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 129819821 - 2¹⁸ = 129557677 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129819841) 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, 56915 + ... + 59151.

It is an arithmetic number, because the mean of its divisors is an integer number (16395588).

Almost surely, 2^129819821 is an apocalyptic number.

It is an amenable number.

129819821 is a deficient number, since it is larger than the sum of its proper divisors (1344883).

129819821 is a wasteful number, since it uses less digits than its factorization.

129819821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2811.

The product of its digits is 20736, while the sum is 41.

The square root of 129819821 is about 11393.8501394393. The cubic root of 129819821 is about 506.3455551782.

The spelling of 129819821 in words is "one hundred twenty-nine million, eight hundred nineteen thousand, eight hundred twenty-one".