20740221 has 24 divisors (see below), whose sum is σ = 31898880. Its totient is φ = 12940416.

The previous prime is 20740217. The next prime is 20740241. The reversal of 20740221 is 12204702.

It is not a de Polignac number, because 20740221 - 2² = 20740217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20740194 and 20740203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20740201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43060 + ... + 43538.

It is an arithmetic number, because the mean of its divisors is an integer number (1329120).

Almost surely, 2^20740221 is an apocalyptic number.

It is an amenable number.

20740221 is a deficient number, since it is larger than the sum of its proper divisors (11158659).

20740221 is a wasteful number, since it uses less digits than its factorization.

20740221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 782 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 20740221 is about 4554.1432783785. The cubic root of 20740221 is about 274.7500583015.

Adding to 20740221 its reverse (12204702), we get a palindrome (32944923).

The spelling of 20740221 in words is "twenty million, seven hundred forty thousand, two hundred twenty-one".