21100280657 has 2 divisors, whose sum is σ = 21100280658. Its totient is φ = 21100280656.

The previous prime is 21100280633. The next prime is 21100280681. The reversal of 21100280657 is 75608200112.

It is a balanced prime because it is at equal distance from previous prime (21100280633) and next prime (21100280681).

It can be written as a sum of positive squares in only one way, i.e., 15829665856 + 5270614801 = 125816^2 + 72599^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100280657 - 2¹⁰ = 21100279633 is a prime.

It is not a weakly prime, because it can be changed into another prime (21100220657) 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, 10550140328 + 10550140329.

It is an arithmetic number, because the mean of its divisors is an integer number (10550140329).

Almost surely, 2^21100280657 is an apocalyptic number.

It is an amenable number.

21100280657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100280657 is an equidigital number, since it uses as much as digits as its factorization.

21100280657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6720, while the sum is 32.

Adding to 21100280657 its reverse (75608200112), we get a palindrome (96708480769).

The spelling of 21100280657 in words is "twenty-one billion, one hundred million, two hundred eighty thousand, six hundred fifty-seven".