21621706055 has 8 divisors (see below), whose sum is σ = 25961133744. Its totient is φ = 17287307200.

The previous prime is 21621706049. The next prime is 21621706069. The reversal of 21621706055 is 55060712612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21621706055 - 2¹⁴ = 21621689671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 1247741 + ... + 1264950.

It is an arithmetic number, because the mean of its divisors is an integer number (3245141718).

Almost surely, 2^21621706055 is an apocalyptic number.

21621706055 is a deficient number, since it is larger than the sum of its proper divisors (4339427689).

21621706055 is a wasteful number, since it uses less digits than its factorization.

21621706055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2514417.

The product of its (nonzero) digits is 25200, while the sum is 35.

The spelling of 21621706055 in words is "twenty-one billion, six hundred twenty-one million, seven hundred six thousand, fifty-five".