21449999873 has 2 divisors, whose sum is σ = 21449999874. Its totient is φ = 21449999872.

The previous prime is 21449999827. The next prime is 21449999881. The reversal of 21449999873 is 37899994412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20876493169 + 573506704 = 144487^2 + 23948^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21449999873 is a prime.

It is a super-2 number, since 2×21449999873² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21449999173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10724999936 + 10724999937.

It is an arithmetic number, because the mean of its divisors is an integer number (10724999937).

Almost surely, 2^21449999873 is an apocalyptic number.

It is an amenable number.

21449999873 is a deficient number, since it is larger than the sum of its proper divisors (1).

21449999873 is an equidigital number, since it uses as much as digits as its factorization.

21449999873 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35271936, while the sum is 65.

The spelling of 21449999873 in words is "twenty-one billion, four hundred forty-nine million, nine hundred ninety-nine thousand, eight hundred seventy-three".