21846128021 has 2 divisors, whose sum is σ = 21846128022. Its totient is φ = 21846128020.

The previous prime is 21846127999. The next prime is 21846128053. The reversal of 21846128021 is 12082164812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13950916996 + 7895211025 = 118114^2 + 88855^2 .

It is a cyclic number.

It is not a de Polignac number, because 21846128021 - 2⁶ = 21846127957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21846124021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923064010 + 10923064011.

It is an arithmetic number, because the mean of its divisors is an integer number (10923064011).

Almost surely, 2^21846128021 is an apocalyptic number.

It is an amenable number.

21846128021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21846128021 is an equidigital number, since it uses as much as digits as its factorization.

21846128021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12288, while the sum is 35.

The spelling of 21846128021 in words is "twenty-one billion, eight hundred forty-six million, one hundred twenty-eight thousand, twenty-one".