28212124621 has 2 divisors, whose sum is σ = 28212124622. Its totient is φ = 28212124620.

The previous prime is 28212124609. The next prime is 28212124657. The reversal of 28212124621 is 12642121282.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15490540521 + 12721584100 = 124461^2 + 112790^2 .

It is a cyclic number.

It is not a de Polignac number, because 28212124621 - 2¹¹ = 28212122573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28212124021) 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 as a sum of consecutive naturals, namely, 14106062310 + 14106062311.

It is an arithmetic number, because the mean of its divisors is an integer number (14106062311).

Almost surely, 2^28212124621 is an apocalyptic number.

It is an amenable number.

28212124621 is a deficient number, since it is larger than the sum of its proper divisors (1).

28212124621 is an equidigital number, since it uses as much as digits as its factorization.

28212124621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 31.

The spelling of 28212124621 in words is "twenty-eight billion, two hundred twelve million, one hundred twenty-four thousand, six hundred twenty-one".