2101221 has 12 divisors (see below), whose sum is σ = 3147872. Its totient is φ = 1400652.

The previous prime is 2101219. The next prime is 2101223. The reversal of 2101221 is 1221012.

It is an interprime number because it is at equal distance from previous prime (2101219) and next prime (2101223).

It is not a de Polignac number, because 2101221 - 2¹ = 2101219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101223) 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, 4081 + ... + 4566.

2^2101221 is an apocalyptic number.

It is an amenable number.

2101221 is a deficient number, since it is larger than the sum of its proper divisors (1046651).

2101221 is an frugal number, since it uses more digits than its factorization.

2101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8662 (or 8650 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 2101221 is about 1449.5588984239. The cubic root of 2101221 is about 128.0827305340.

Adding to 2101221 its reverse (1221012), we get a palindrome (3322233).

It can be divided in two parts, 210 and 1221, that added together give a triangular number (1431 = T₅₃).

The spelling of 2101221 in words is "two million, one hundred one thousand, two hundred twenty-one".