20018729 has 8 divisors (see below), whose sum is σ = 21020160. Its totient is φ = 19038096.

The previous prime is 20018659. The next prime is 20018743. The reversal of 20018729 is 92781002.

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 a de Polignac number, because none of the positive numbers 2^k-20018729 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20018429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3209 + ... + 7094.

It is an arithmetic number, because the mean of its divisors is an integer number (2627520).

Almost surely, 2^20018729 is an apocalyptic number.

20018729 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20018729 is a deficient number, since it is larger than the sum of its proper divisors (1001431).

20018729 is a wasteful number, since it uses less digits than its factorization.

20018729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10399.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20018729 is about 4474.2294308629. The cubic root of 20018729 is about 271.5264657705.

The spelling of 20018729 in words is "twenty million, eighteen thousand, seven hundred twenty-nine".