21454460981 has 2 divisors, whose sum is σ = 21454460982. Its totient is φ = 21454460980.

The previous prime is 21454460977. The next prime is 21454461163. The reversal of 21454460981 is 18906445412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20230510756 + 1223950225 = 142234^2 + 34985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21454460981 - 2² = 21454460977 is a prime.

It is a super-2 number, since 2×21454460981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21454460281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727230490 + 10727230491.

It is an arithmetic number, because the mean of its divisors is an integer number (10727230491).

Almost surely, 2^21454460981 is an apocalyptic number.

It is an amenable number.

21454460981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454460981 is an equidigital number, since it uses as much as digits as its factorization.

21454460981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 276480, while the sum is 44.

The spelling of 21454460981 in words is "twenty-one billion, four hundred fifty-four million, four hundred sixty thousand, nine hundred eighty-one".