21206705520454 has 16 divisors (see below), whose sum is σ = 32154611653440. Its totient is φ = 10488870340480.

The previous prime is 21206705520449. The next prime is 21206705520467. The reversal of 21206705520454 is 45402550760212.

It is a super-2 number, since 2×21206705520454² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21206705520454.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92060782 + ... + 92290849.

It is an arithmetic number, because the mean of its divisors is an integer number (2009663228340).

Almost surely, 2^{21206705520454} is an apocalyptic number.

21206705520454 is a deficient number, since it is larger than the sum of its proper divisors (10947906132986).

21206705520454 is a wasteful number, since it uses less digits than its factorization.

21206705520454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184352255.

The product of its (nonzero) digits is 672000, while the sum is 43.

The spelling of 21206705520454 in words is "twenty-one trillion, two hundred six billion, seven hundred five million, five hundred twenty thousand, four hundred fifty-four".