228122021 has 4 divisors (see below), whose sum is σ = 228156492. Its totient is φ = 228087552.

The previous prime is 228121979. The next prime is 228122023. The reversal of 228122021 is 120221822.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 150945796 + 77176225 = 12286^2 + 8785^2 .

It is a cyclic number.

It is not a de Polignac number, because 228122021 - 2²⁶ = 161013157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 228121984 and 228122002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228122023) 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, 3836 + ... + 21701.

It is an arithmetic number, because the mean of its divisors is an integer number (57039123).

Almost surely, 2^228122021 is an apocalyptic number.

It is an amenable number.

228122021 is a deficient number, since it is larger than the sum of its proper divisors (34471).

228122021 is an equidigital number, since it uses as much as digits as its factorization.

228122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34470.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 228122021 is about 15103.7088491536. The cubic root of 228122021 is about 611.0204374916.

Adding to 228122021 its reverse (120221822), we get a palindrome (348343843).

The spelling of 228122021 in words is "two hundred twenty-eight million, one hundred twenty-two thousand, twenty-one".