221023021 has 8 divisors (see below), whose sum is σ = 222587064. Its totient is φ = 219463680.

The previous prime is 221023013. The next prime is 221023037. The reversal of 221023021 is 120320122.

221023021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 11902500 + 209120521 = 3450^2 + 14461^2 .

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 221023021 - 2³ = 221023013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221022992 and 221023010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221083021) 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, 181005 + ... + 182221.

It is an arithmetic number, because the mean of its divisors is an integer number (27823383).

Almost surely, 2^221023021 is an apocalyptic number.

It is an amenable number.

221023021 is a deficient number, since it is larger than the sum of its proper divisors (1564043).

221023021 is a wasteful number, since it uses less digits than its factorization.

221023021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2351.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 221023021 is about 14866.8430071754. The cubic root of 221023021 is about 604.6153518841.

Adding to 221023021 its reverse (120320122), we get a palindrome (341343143).

The spelling of 221023021 in words is "two hundred twenty-one million, twenty-three thousand, twenty-one".