21124005451 has 2 divisors, whose sum is σ = 21124005452. Its totient is φ = 21124005450.

The previous prime is 21124005443. The next prime is 21124005467. The reversal of 21124005451 is 15450042112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21124005451 - 2³ = 21124005443 is a prime.

It is not a weakly prime, because it can be changed into another prime (21124005481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562002725 + 10562002726.

It is an arithmetic number, because the mean of its divisors is an integer number (10562002726).

Almost surely, 2^21124005451 is an apocalyptic number.

21124005451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124005451 is an equidigital number, since it uses as much as digits as its factorization.

21124005451 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21124005451 its reverse (15450042112), we get a palindrome (36574047563).

The spelling of 21124005451 in words is "twenty-one billion, one hundred twenty-four million, five thousand, four hundred fifty-one".