20613729 has 8 divisors (see below), whose sum is σ = 28371712. Its totient is φ = 13299120.

The previous prime is 20613647. The next prime is 20613731. The reversal of 20613729 is 92731602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20613729 - 2⁷ = 20613601 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20613696 and 20613705.

It is not an unprimeable number, because it can be changed into a prime (20613029) 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 7 ways as a sum of consecutive naturals, for example, 110734 + ... + 110919.

It is an arithmetic number, because the mean of its divisors is an integer number (3546464).

Almost surely, 2^20613729 is an apocalyptic number.

It is an amenable number.

20613729 is a deficient number, since it is larger than the sum of its proper divisors (7757983).

20613729 is a wasteful number, since it uses less digits than its factorization.

20613729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221687.

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 20613729 is about 4540.2344653112. The cubic root of 20613729 is about 274.1903635659.

The spelling of 20613729 in words is "twenty million, six hundred thirteen thousand, seven hundred twenty-nine".