72222228 has 36 divisors (see below), whose sum is σ = 196606228. Its totient is φ = 22222080.

The previous prime is 72222193. The next prime is 72222229. The reversal of 72222228 is 82222227.

It can be written as a sum of positive squares in 2 ways, for example, as 7387524 + 64834704 = 2718^2 + 8052^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72222229) 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, 76693 + ... + 77628.

Almost surely, 2^72222228 is an apocalyptic number.

72222228 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is an amenable number.

72222228 is an abundant number, since it is smaller than the sum of its proper divisors (124384000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

72222228 is a wasteful number, since it uses less digits than its factorization.

72222228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154344 (or 154339 counting only the distinct ones).

The product of its digits is 3584, while the sum is 27.

The square root of 72222228 is about 8498.3661959226. The cubic root of 72222228 is about 416.4443369256. Note that the first 3 decimals are identical.

Subtracting 72222228 from its reverse (82222227), we obtain a palindrome (9999999).

The spelling of 72222228 in words is "seventy-two million, two hundred twenty-two thousand, two hundred twenty-eight".