21006046663 has 4 divisors (see below), whose sum is σ = 24006910480. Its totient is φ = 18005182848.

The previous prime is 21006046639. The next prime is 21006046669. The reversal of 21006046663 is 36664060012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21006046663 - 2²¹ = 21003949511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006046669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500431898 + ... + 1500431911.

It is an arithmetic number, because the mean of its divisors is an integer number (6001727620).

Almost surely, 2^21006046663 is an apocalyptic number.

21006046663 is a deficient number, since it is larger than the sum of its proper divisors (3000863817).

21006046663 is an equidigital number, since it uses as much as digits as its factorization.

21006046663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3000863816.

The product of its (nonzero) digits is 31104, while the sum is 34.

The spelling of 21006046663 in words is "twenty-one billion, six million, forty-six thousand, six hundred sixty-three".