21278168341 has 2 divisors, whose sum is σ = 21278168342. Its totient is φ = 21278168340.

The previous prime is 21278168311. The next prime is 21278168369. The reversal of 21278168341 is 14386187212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18585596241 + 2692572100 = 136329^2 + 51890^2 .

It is a cyclic number.

It is not a de Polignac number, because 21278168341 - 2¹⁵ = 21278135573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21278168311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10639084170 + 10639084171.

It is an arithmetic number, because the mean of its divisors is an integer number (10639084171).

Almost surely, 2^21278168341 is an apocalyptic number.

It is an amenable number.

21278168341 is a deficient number, since it is larger than the sum of its proper divisors (1).

21278168341 is an equidigital number, since it uses as much as digits as its factorization.

21278168341 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129024, while the sum is 43.

The spelling of 21278168341 in words is "twenty-one billion, two hundred seventy-eight million, one hundred sixty-eight thousand, three hundred forty-one".