20129447 has 16 divisors (see below), whose sum is σ = 22579200. Its totient is φ = 17820000.

The previous prime is 20129429. The next prime is 20129471. The reversal of 20129447 is 74492102.

It is a cyclic number.

It is not a de Polignac number, because 20129447 - 2⁶ = 20129383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20129407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80072 + ... + 80322.

It is an arithmetic number, because the mean of its divisors is an integer number (1411200).

Almost surely, 2^20129447 is an apocalyptic number.

20129447 is a deficient number, since it is larger than the sum of its proper divisors (2449753).

20129447 is a wasteful number, since it uses less digits than its factorization.

20129447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 20129447 is about 4486.5852270964. The cubic root of 20129447 is about 272.0261247615.

The spelling of 20129447 in words is "twenty million, one hundred twenty-nine thousand, four hundred forty-seven".