21242400666 has 8 divisors (see below), whose sum is σ = 42484801344. Its totient is φ = 7080800220.

The previous prime is 21242400623. The next prime is 21242400703. The reversal of 21242400666 is 66600424212.

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

21242400666 is an admirable 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, 1770200050 + ... + 1770200061.

It is an arithmetic number, because the mean of its divisors is an integer number (5310600168).

Almost surely, 2^21242400666 is an apocalyptic number.

21242400666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21242400666 is a wasteful number, since it uses less digits than its factorization.

21242400666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3540400116.

The product of its (nonzero) digits is 27648, while the sum is 33.

Adding to 21242400666 its reverse (66600424212), we get a palindrome (87842824878).

The spelling of 21242400666 in words is "twenty-one billion, two hundred forty-two million, four hundred thousand, six hundred sixty-six".