21846011021 has 2 divisors, whose sum is σ = 21846011022. Its totient is φ = 21846011020.

The previous prime is 21846010999. The next prime is 21846011027. The reversal of 21846011021 is 12011064812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20131636996 + 1714374025 = 141886^2 + 41405^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21846011021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21846011027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923005510 + 10923005511.

It is an arithmetic number, because the mean of its divisors is an integer number (10923005511).

Almost surely, 2^21846011021 is an apocalyptic number.

It is an amenable number.

21846011021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21846011021 is an equidigital number, since it uses as much as digits as its factorization.

21846011021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 26.

Adding to 21846011021 its reverse (12011064812), we get a palindrome (33857075833).

The spelling of 21846011021 in words is "twenty-one billion, eight hundred forty-six million, eleven thousand, twenty-one".