20939729 has 8 divisors (see below), whose sum is σ = 23000640. Its totient is φ = 18974736.

The previous prime is 20939719. The next prime is 20939731. The reversal of 20939729 is 92793902.

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 20939729 - 2⁸ = 20939473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20939719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23522 + ... + 24395.

It is an arithmetic number, because the mean of its divisors is an integer number (2875080).

Almost surely, 2^20939729 is an apocalyptic number.

It is an amenable number.

20939729 is a deficient number, since it is larger than the sum of its proper divisors (2060911).

20939729 is a wasteful number, since it uses less digits than its factorization.

20939729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47959.

The product of its (nonzero) digits is 61236, while the sum is 41.

The square root of 20939729 is about 4575.9948645076. The cubic root of 20939729 is about 275.6282232678.

The spelling of 20939729 in words is "twenty million, nine hundred thirty-nine thousand, seven hundred twenty-nine".