21036449663 has 4 divisors (see below), whose sum is σ = 21079294248. Its totient is φ = 20993605080.

The previous prime is 21036449657. The next prime is 21036449671. The reversal of 21036449663 is 36694463012.

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 21036449663 - 2⁴ = 21036449647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036442663) 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, 21421556 + ... + 21422537.

It is an arithmetic number, because the mean of its divisors is an integer number (5269823562).

Almost surely, 2^21036449663 is an apocalyptic number.

21036449663 is a deficient number, since it is larger than the sum of its proper divisors (42844585).

21036449663 is an equidigital number, since it uses as much as digits as its factorization.

21036449663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42844584.

The product of its (nonzero) digits is 559872, while the sum is 44.

The spelling of 21036449663 in words is "twenty-one billion, thirty-six million, four hundred forty-nine thousand, six hundred sixty-three".