21036451 has 2 divisors, whose sum is σ = 21036452. Its totient is φ = 21036450.

The previous prime is 21036443. The next prime is 21036469. The reversal of 21036451 is 15463012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21036451 - 2³ = 21036443 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21036481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518225 + 10518226.

It is an arithmetic number, because the mean of its divisors is an integer number (10518226).

Almost surely, 2^21036451 is an apocalyptic number.

21036451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21036451 is an equidigital number, since it uses as much as digits as its factorization.

21036451 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21036451 is about 4586.5511007728. The cubic root of 21036451 is about 276.0519532179.

Adding to 21036451 its reverse (15463012), we get a palindrome (36499463).

The spelling of 21036451 in words is "twenty-one million, thirty-six thousand, four hundred fifty-one".