21681667006 has 16 divisors (see below), whose sum is σ = 32743678464. Its totient is φ = 10767195864.

The previous prime is 21681666977. The next prime is 21681667013. The reversal of 21681667006 is 60076618612.

It is a happy number.

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, 489621 + ... + 532063.

It is an arithmetic number, because the mean of its divisors is an integer number (2046479904).

Almost surely, 2^21681667006 is an apocalyptic number.

21681667006 is a deficient number, since it is larger than the sum of its proper divisors (11062011458).

21681667006 is a wasteful number, since it uses less digits than its factorization.

21681667006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44175.

The product of its (nonzero) digits is 145152, while the sum is 43.

The spelling of 21681667006 in words is "twenty-one billion, six hundred eighty-one million, six hundred sixty-seven thousand, six".