21655223406646 has 8 divisors (see below), whose sum is σ = 32689732149360. Its totient is φ = 10758646023528.

The previous prime is 21655223406611. The next prime is 21655223406671. The reversal of 21655223406646 is 64660432255612.

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

It is a junction number, because it is equal to n+sod(n) for n = 21655223406593 and 21655223406602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34482839506 + ... + 34482840133.

It is an arithmetic number, because the mean of its divisors is an integer number (4086216518670).

Almost surely, 2^{21655223406646} is an apocalyptic number.

21655223406646 is a deficient number, since it is larger than the sum of its proper divisors (11034508742714).

21655223406646 is a wasteful number, since it uses less digits than its factorization.

21655223406646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68965679798.

The product of its (nonzero) digits is 12441600, while the sum is 52.

The spelling of 21655223406646 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twenty-three million, four hundred six thousand, six hundred forty-six".