28220304121 has 9 divisors (see below), whose sum is σ = 29165384133. Its totient is φ = 27304932060.

The previous prime is 28220304107. The next prime is 28220304131. The reversal of 28220304121 is 12140302282.

The square root of 28220304121 is 167989.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 28220304121 - 2⁹ = 28220303609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28220304131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5204950 + ... + 5210368.

It is an arithmetic number, because the mean of its divisors is an integer number (3240598237).

Almost surely, 2^28220304121 is an apocalyptic number.

28220304121 is the 167989-th square number.

28220304121 is the 83995-th centered octagonal number.

It is an amenable number.

28220304121 is a deficient number, since it is larger than the sum of its proper divisors (945080012).

28220304121 is an frugal number, since it uses more digits than its factorization.

28220304121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10900 (or 5450 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

Multiplying 28220304121 by its sum of digits (25), we get a square (705507603025 = 839945²).

The spelling of 28220304121 in words is "twenty-eight billion, two hundred twenty million, three hundred four thousand, one hundred twenty-one".