211620221 has 8 divisors (see below), whose sum is σ = 219088800. Its totient is φ = 204163120.

The previous prime is 211620209. The next prime is 211620259. The reversal of 211620221 is 122026112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 211620221 - 2¹⁴ = 211603837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 211620221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211625221) 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, 54110 + ... + 57888.

It is an arithmetic number, because the mean of its divisors is an integer number (27386100).

Almost surely, 2^211620221 is an apocalyptic number.

It is an amenable number.

211620221 is a deficient number, since it is larger than the sum of its proper divisors (7468579).

211620221 is a wasteful number, since it uses less digits than its factorization.

211620221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5739.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 211620221 is about 14547.1722681764. The cubic root of 211620221 is about 595.9169262844.

Adding to 211620221 its reverse (122026112), we get a palindrome (333646333).

The spelling of 211620221 in words is "two hundred eleven million, six hundred twenty thousand, two hundred twenty-one".