21654103400666 has 16 divisors (see below), whose sum is σ = 35434347969888. Its totient is φ = 9842674110000.

The previous prime is 21654103400663. The next prime is 21654103400669. The reversal of 21654103400666 is 66600430145612.

It is an interprime number because it is at equal distance from previous prime (21654103400663) and next prime (21654103400669).

It is not an unprimeable number, because it can be changed into a prime (21654103400663) 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, 2775005 + ... + 7142048.

It is an arithmetic number, because the mean of its divisors is an integer number (2214646748118).

Almost surely, 2^{21654103400666} is an apocalyptic number.

21654103400666 is a deficient number, since it is larger than the sum of its proper divisors (13780244569222).

21654103400666 is a wasteful number, since it uses less digits than its factorization.

21654103400666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10016317.

The product of its (nonzero) digits is 622080, while the sum is 44.

The spelling of 21654103400666 in words is "twenty-one trillion, six hundred fifty-four billion, one hundred three million, four hundred thousand, six hundred sixty-six".