20670221 has 12 divisors (see below), whose sum is σ = 24419520. Its totient is φ = 17344080.

The previous prime is 20670217. The next prime is 20670241. The reversal of 20670221 is 12207602.

It is not a de Polignac number, because 20670221 - 2² = 20670217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20670193 and 20670202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20670241) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3701 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (2034960).

Almost surely, 2^20670221 is an apocalyptic number.

It is an amenable number.

20670221 is a deficient number, since it is larger than the sum of its proper divisors (3749299).

20670221 is a wasteful number, since it uses less digits than its factorization.

20670221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11156 (or 11143 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20670221 is about 4546.4514734021. The cubic root of 20670221 is about 274.4406083387.

Adding to 20670221 its reverse (12207602), we get a palindrome (32877823).

The spelling of 20670221 in words is "twenty million, six hundred seventy thousand, two hundred twenty-one".