21660424021406 has 16 divisors (see below), whose sum is σ = 32620388428800. Its totient is φ = 10787045114040.

The previous prime is 21660424021373. The next prime is 21660424021409. The reversal of 21660424021406 is 60412042406612.

It is a self number, because there is not a number n which added to its sum of digits gives 21660424021406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660424021409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20458706 + ... + 21491381.

It is an arithmetic number, because the mean of its divisors is an integer number (2038774276800).

Almost surely, 2^{21660424021406} is an apocalyptic number.

21660424021406 is a deficient number, since it is larger than the sum of its proper divisors (10959964407394).

21660424021406 is a wasteful number, since it uses less digits than its factorization.

21660424021406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41951119.

The product of its (nonzero) digits is 110592, while the sum is 38.

The spelling of 21660424021406 in words is "twenty-one trillion, six hundred sixty billion, four hundred twenty-four million, twenty-one thousand, four hundred six".