28402837721 has 2 divisors, whose sum is σ = 28402837722. Its totient is φ = 28402837720.

The previous prime is 28402837681. The next prime is 28402837739. The reversal of 28402837721 is 12773820482.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23998657225 + 4404180496 = 154915^2 + 66364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28402837721 is a prime.

It is not a weakly prime, because it can be changed into another prime (28402837321) 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, 14201418860 + 14201418861.

It is an arithmetic number, because the mean of its divisors is an integer number (14201418861).

Almost surely, 2^28402837721 is an apocalyptic number.

It is an amenable number.

28402837721 is a deficient number, since it is larger than the sum of its proper divisors (1).

28402837721 is an equidigital number, since it uses as much as digits as its factorization.

28402837721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 301056, while the sum is 44.

The spelling of 28402837721 in words is "twenty-eight billion, four hundred two million, eight hundred thirty-seven thousand, seven hundred twenty-one".