221516211 has 24 divisors (see below), whose sum is σ = 344181504. Its totient is φ = 126357840.

The previous prime is 221516209. The next prime is 221516219. The reversal of 221516211 is 112615122.

It is not a de Polignac number, because 221516211 - 2¹ = 221516209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (221516219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120066 + ... + 121896.

It is an arithmetic number, because the mean of its divisors is an integer number (14340896).

Almost surely, 2^221516211 is an apocalyptic number.

221516211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

221516211 is a deficient number, since it is larger than the sum of its proper divisors (122665293).

221516211 is a wasteful number, since it uses less digits than its factorization.

221516211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2671 (or 2664 counting only the distinct ones).

The product of its digits is 240, while the sum is 21.

The square root of 221516211 is about 14883.4206753690. The cubic root of 221516211 is about 605.0647300002.

The spelling of 221516211 in words is "two hundred twenty-one million, five hundred sixteen thousand, two hundred eleven".