20720713 has 8 divisors (see below), whose sum is σ = 22566600. Its totient is φ = 18910848.

The previous prime is 20720681. The next prime is 20720717. The reversal of 20720713 is 31702702.

It can be written as a sum of positive squares in 4 ways, for example, as 9 + 20720704 = 3^2 + 4552^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20720713 - 2⁵ = 20720681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20720717) 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, 7798 + ... + 10111.

It is an arithmetic number, because the mean of its divisors is an integer number (2820825).

Almost surely, 2^20720713 is an apocalyptic number.

It is an amenable number.

20720713 is a deficient number, since it is larger than the sum of its proper divisors (1845887).

20720713 is a wasteful number, since it uses less digits than its factorization.

20720713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18011.

The product of its (nonzero) digits is 588, while the sum is 22.

The square root of 20720713 is about 4552.0009885763. Note that the first 3 decimals coincide. The cubic root of 20720713 is about 274.6638890899.

The spelling of 20720713 in words is "twenty million, seven hundred twenty thousand, seven hundred thirteen".