21405704042454 has 16 divisors (see below), whose sum is σ = 42812459444160. Its totient is φ = 7135059454280.

The previous prime is 21405704042453. The next prime is 21405704042467. The reversal of 21405704042454 is 45424040750412.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405704042453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43541832 + ... + 44030699.

It is an arithmetic number, because the mean of its divisors is an integer number (2675778715260).

Almost surely, 2^{21405704042454} is an apocalyptic number.

21405704042454 is an abundant number, since it is smaller than the sum of its proper divisors (21406755401706).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21405704042454 is a wasteful number, since it uses less digits than its factorization.

21405704042454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87613275.

The product of its (nonzero) digits is 716800, while the sum is 42.

Adding to 21405704042454 its reverse (45424040750412), we get a palindrome (66829744792866).

The spelling of 21405704042454 in words is "twenty-one trillion, four hundred five billion, seven hundred four million, forty-two thousand, four hundred fifty-four".