21063646012 has 24 divisors (see below), whose sum is σ = 40053117440. Its totient is φ = 9655660080.

The previous prime is 21063645947. The next prime is 21063646027. The reversal of 21063646012 is 21064636012.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4467858 + ... + 4472569.

Almost surely, 2^21063646012 is an apocalyptic number.

It is an amenable number.

21063646012 is a deficient number, since it is larger than the sum of its proper divisors (18989471428).

21063646012 is a wasteful number, since it uses less digits than its factorization.

21063646012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8940481 (or 8940479 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

The spelling of 21063646012 in words is "twenty-one billion, sixty-three million, six hundred forty-six thousand, twelve".