21455861062417 has 4 divisors (see below), whose sum is σ = 21599860130100. Its totient is φ = 21311861994736.

The previous prime is 21455861062399. The next prime is 21455861062477. The reversal of 21455861062417 is 71426016855412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 915713111041 + 20540147951376 = 956929^2 + 4532124^2 .

It is a cyclic number.

It is not a de Polignac number, because 21455861062417 - 2¹¹ = 21455861060369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21455861062477) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71999533618 + ... + 71999533915.

It is an arithmetic number, because the mean of its divisors is an integer number (5399965032525).

Almost surely, 2^{21455861062417} is an apocalyptic number.

It is an amenable number.

21455861062417 is a deficient number, since it is larger than the sum of its proper divisors (143999067683).

21455861062417 is a wasteful number, since it uses less digits than its factorization.

21455861062417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143999067682.

The product of its (nonzero) digits is 3225600, while the sum is 52.

The spelling of 21455861062417 in words is "twenty-one trillion, four hundred fifty-five billion, eight hundred sixty-one million, sixty-two thousand, four hundred seventeen".