21768667684 has 12 divisors (see below), whose sum is σ = 38103156700. Its totient is φ = 10882051488.

The previous prime is 21768667673. The next prime is 21768667693. The reversal of 21768667684 is 48676686712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9162318400 + 12606349284 = 95720^2 + 112278^2 .

It is a hoax number, since the sum of its digits (61) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549039 + ... + 587350.

Almost surely, 2^21768667684 is an apocalyptic number.

It is an amenable number.

21768667684 is a deficient number, since it is larger than the sum of its proper divisors (16334489016).

21768667684 is a wasteful number, since it uses less digits than its factorization.

21768667684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141182 (or 1141180 counting only the distinct ones).

The product of its digits is 32514048, while the sum is 61.

The spelling of 21768667684 in words is "twenty-one billion, seven hundred sixty-eight million, six hundred sixty-seven thousand, six hundred eighty-four".