21018134281 has 2 divisors, whose sum is σ = 21018134282. Its totient is φ = 21018134280.

The previous prime is 21018134273. The next prime is 21018134317. The reversal of 21018134281 is 18243181012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20573599225 + 444535056 = 143435^2 + 21084^2 .

It is a cyclic number.

It is not a de Polignac number, because 21018134281 - 2³ = 21018134273 is a prime.

It is a super-2 number, since 2×21018134281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21018134201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509067140 + 10509067141.

It is an arithmetic number, because the mean of its divisors is an integer number (10509067141).

Almost surely, 2^21018134281 is an apocalyptic number.

It is an amenable number.

21018134281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21018134281 is an equidigital number, since it uses as much as digits as its factorization.

21018134281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 31.

The spelling of 21018134281 in words is "twenty-one billion, eighteen million, one hundred thirty-four thousand, two hundred eighty-one".