21004024451 has 2 divisors, whose sum is σ = 21004024452. Its totient is φ = 21004024450.

The previous prime is 21004024441. The next prime is 21004024471. The reversal of 21004024451 is 15442040012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21004024451 - 2²² = 20999830147 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004024441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502012225 + 10502012226.

It is an arithmetic number, because the mean of its divisors is an integer number (10502012226).

Almost surely, 2^21004024451 is an apocalyptic number.

21004024451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004024451 is an equidigital number, since it uses as much as digits as its factorization.

21004024451 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1280, while the sum is 23.

Adding to 21004024451 its reverse (15442040012), we get a palindrome (36446064463).

The spelling of 21004024451 in words is "twenty-one billion, four million, twenty-four thousand, four hundred fifty-one".