20713729 has 4 divisors (see below), whose sum is σ = 20963376. Its totient is φ = 20464084.

The previous prime is 20713703. The next prime is 20713741. The reversal of 20713729 is 92731702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20713729 - 2⁵ = 20713697 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20713729.

It is not an unprimeable number, because it can be changed into a prime (20713799) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124699 + ... + 124864.

It is an arithmetic number, because the mean of its divisors is an integer number (5240844).

Almost surely, 2^20713729 is an apocalyptic number.

It is an amenable number.

20713729 is a deficient number, since it is larger than the sum of its proper divisors (249647).

20713729 is an equidigital number, since it uses as much as digits as its factorization.

20713729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249646.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 20713729 is about 4551.2337887654. The cubic root of 20713729 is about 274.6330267645.

The spelling of 20713729 in words is "twenty million, seven hundred thirteen thousand, seven hundred twenty-nine".