21658770668406 has 16 divisors (see below), whose sum is σ = 43341460486848. Its totient is φ = 7215603697800.

The previous prime is 21658770668383. The next prime is 21658770668443. The reversal of 21658770668406 is 60486607785612.

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, 996619480 + ... + 996641211.

It is an arithmetic number, because the mean of its divisors is an integer number (2708841280428).

Almost surely, 2^{21658770668406} is an apocalyptic number.

21658770668406 is an abundant number, since it is smaller than the sum of its proper divisors (21682689818442).

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

21658770668406 is a wasteful number, since it uses less digits than its factorization.

21658770668406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1993262507.

The product of its (nonzero) digits is 162570240, while the sum is 66.

The spelling of 21658770668406 in words is "twenty-one trillion, six hundred fifty-eight billion, seven hundred seventy million, six hundred sixty-eight thousand, four hundred six".