20729045 has 4 divisors (see below), whose sum is σ = 24874860. Its totient is φ = 16583232.

The previous prime is 20729041. The next prime is 20729077. The reversal of 20729045 is 54092702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4656964 + 16072081 = 2158^2 + 4009^2 .

It is a cyclic number.

It is not a de Polignac number, because 20729045 - 2² = 20729041 is a prime.

It is a super-2 number, since 2×20729045² = 859386613224050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20728999 and 20729017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20729041) 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, 2072900 + ... + 2072909.

It is an arithmetic number, because the mean of its divisors is an integer number (6218715).

Almost surely, 2^20729045 is an apocalyptic number.

It is an amenable number.

20729045 is a deficient number, since it is larger than the sum of its proper divisors (4145815).

20729045 is an equidigital number, since it uses as much as digits as its factorization.

20729045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4145814.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20729045 is about 4552.9160985021. The cubic root of 20729045 is about 274.7006991625.

The spelling of 20729045 in words is "twenty million, seven hundred twenty-nine thousand, forty-five".