21620206 has 16 divisors (see below), whose sum is σ = 33799680. Its totient is φ = 10360440.

The previous prime is 21620197. The next prime is 21620227. The reversal of 21620206 is 60202612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5005 + ... + 8263.

It is an arithmetic number, because the mean of its divisors is an integer number (2112480).

Almost surely, 2^21620206 is an apocalyptic number.

21620206 is a deficient number, since it is larger than the sum of its proper divisors (12179474).

21620206 is a wasteful number, since it uses less digits than its factorization.

21620206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3399.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21620206 is about 4649.7533267906. The cubic root of 21620206 is about 278.5821436409.

Adding to 21620206 its reverse (60202612), we get a palindrome (81822818).

The spelling of 21620206 in words is "twenty-one million, six hundred twenty thousand, two hundred six".