20707221 has 16 divisors (see below), whose sum is σ = 28435968. Its totient is φ = 13398000.

The previous prime is 20707187. The next prime is 20707229. The reversal of 20707221 is 12270702.

It is not a de Polignac number, because 20707221 - 2⁶ = 20707157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20707229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13546 + ... + 14996.

It is an arithmetic number, because the mean of its divisors is an integer number (1777248).

Almost surely, 2^20707221 is an apocalyptic number.

It is an amenable number.

20707221 is a deficient number, since it is larger than the sum of its proper divisors (7728747).

20707221 is a wasteful number, since it uses less digits than its factorization.

20707221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1592.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 20707221 is about 4550.5187616359. The cubic root of 20707221 is about 274.6042616404.

Adding to 20707221 its reverse (12270702), we get a palindrome (32977923).

The spelling of 20707221 in words is "twenty million, seven hundred seven thousand, two hundred twenty-one".