20630721 has 8 divisors (see below), whose sum is σ = 27547264. Its totient is φ = 13734000.

The previous prime is 20630711. The next prime is 20630761. The reversal of 20630721 is 12703602.

It is a happy number.

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

It is not a de Polignac number, because 20630721 - 2⁹ = 20630209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20630711) 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, 2326 + ... + 6831.

It is an arithmetic number, because the mean of its divisors is an integer number (3443408).

Almost surely, 2^20630721 is an apocalyptic number.

It is an amenable number.

20630721 is a deficient number, since it is larger than the sum of its proper divisors (6916543).

20630721 is an equidigital number, since it uses as much as digits as its factorization.

20630721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9911.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 20630721 is about 4542.1053488443. The cubic root of 20630721 is about 274.2656817044.

The spelling of 20630721 in words is "twenty million, six hundred thirty thousand, seven hundred twenty-one".