20729189 has 4 divisors (see below), whose sum is σ = 22323756. Its totient is φ = 19134624.

The previous prime is 20729179. The next prime is 20729221. The reversal of 20729189 is 98192702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98192702 = 2 ⋅49096351.

It can be written as a sum of positive squares in 2 ways, for example, as 9872164 + 10857025 = 3142^2 + 3295^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20729189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20729179) 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 3 ways as a sum of consecutive naturals, for example, 797264 + ... + 797289.

It is an arithmetic number, because the mean of its divisors is an integer number (5580939).

Almost surely, 2^20729189 is an apocalyptic number.

It is an amenable number.

20729189 is a deficient number, since it is larger than the sum of its proper divisors (1594567).

20729189 is a wasteful number, since it uses less digits than its factorization.

20729189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1594566.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 20729189 is about 4552.9319125153. The cubic root of 20729189 is about 274.7013352556.

The spelling of 20729189 in words is "twenty million, seven hundred twenty-nine thousand, one hundred eighty-nine".