221201021 has 4 divisors (see below), whose sum is σ = 232843200. Its totient is φ = 209558844.

The previous prime is 221201017. The next prime is 221201033. The reversal of 221201021 is 120102122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221201021 - 2² = 221201017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221200993 and 221201011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221201041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5821061 + ... + 5821098.

It is an arithmetic number, because the mean of its divisors is an integer number (58210800).

Almost surely, 2^221201021 is an apocalyptic number.

It is an amenable number.

221201021 is a deficient number, since it is larger than the sum of its proper divisors (11642179).

221201021 is a wasteful number, since it uses less digits than its factorization.

221201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11642178.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 221201021 is about 14872.8282784412. The cubic root of 221201021 is about 604.7776165118. Note that the first 3 decimals are identical.

Adding to 221201021 its reverse (120102122), we get a palindrome (341303143).

It can be divided in two parts, 22 and 1201021, that multiplied together give a palindrome (26422462).

The spelling of 221201021 in words is "two hundred twenty-one million, two hundred one thousand, twenty-one".