20129680 has 20 divisors (see below), whose sum is σ = 46801692. Its totient is φ = 8051840.

The previous prime is 20129671. The next prime is 20129687. The reversal of 20129680 is 8692102.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4511376 + 15618304 = 2124^2 + 3952^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (20129687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125731 + ... + 125890.

Almost surely, 2^20129680 is an apocalyptic number.

20129680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20129680 is an abundant number, since it is smaller than the sum of its proper divisors (26672012).

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

20129680 is a wasteful number, since it uses less digits than its factorization.

20129680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251634 (or 251628 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20129680 is about 4486.6111933173. The cubic root of 20129680 is about 272.0271743323.

The spelling of 20129680 in words is "twenty million, one hundred twenty-nine thousand, six hundred eighty".