21042051451 has 2 divisors, whose sum is σ = 21042051452. Its totient is φ = 21042051450.

The previous prime is 21042051421. The next prime is 21042051463. The reversal of 21042051451 is 15415024012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042051451 is a prime.

It is not a weakly prime, because it can be changed into another prime (21042051421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521025725 + 10521025726.

It is an arithmetic number, because the mean of its divisors is an integer number (10521025726).

Almost surely, 2^21042051451 is an apocalyptic number.

21042051451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21042051451 is an equidigital number, since it uses as much as digits as its factorization.

21042051451 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21042051451 its reverse (15415024012), we get a palindrome (36457075463).

The spelling of 21042051451 in words is "twenty-one billion, forty-two million, fifty-one thousand, four hundred fifty-one".