21454051243 has 2 divisors, whose sum is σ = 21454051244. Its totient is φ = 21454051242.

The previous prime is 21454051193. The next prime is 21454051273. The reversal of 21454051243 is 34215045412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21454051243 is a prime.

It is not a weakly prime, because it can be changed into another prime (21454051273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727025621 + 10727025622.

It is an arithmetic number, because the mean of its divisors is an integer number (10727025622).

Almost surely, 2^21454051243 is an apocalyptic number.

21454051243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454051243 is an equidigital number, since it uses as much as digits as its factorization.

21454051243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 21454051243 its reverse (34215045412), we get a palindrome (55669096655).

The spelling of 21454051243 in words is "twenty-one billion, four hundred fifty-four million, fifty-one thousand, two hundred forty-three".