20545221 has 8 divisors (see below), whose sum is σ = 27460384. Its totient is φ = 13663440.

The previous prime is 20545207. The next prime is 20545237. The reversal of 20545221 is 12254502.

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 20545221 - 2¹³ = 20537029 is a prime.

It is a super-2 number, since 2×20545221² = 844212211877682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20545201) 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, 6871 + ... + 9396.

It is an arithmetic number, because the mean of its divisors is an integer number (3432548).

Almost surely, 2^20545221 is an apocalyptic number.

It is an amenable number.

20545221 is a deficient number, since it is larger than the sum of its proper divisors (6915163).

20545221 is a wasteful number, since it uses less digits than its factorization.

20545221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16691.

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 20545221 is about 4532.6836421705. The cubic root of 20545221 is about 273.8862768865.

Adding to 20545221 its reverse (12254502), we get a palindrome (32799723).

The spelling of 20545221 in words is "twenty million, five hundred forty-five thousand, two hundred twenty-one".