21644034963 has 4 divisors (see below), whose sum is σ = 28858713288. Its totient is φ = 14429356640.

The previous prime is 21644034949. The next prime is 21644034983. The reversal of 21644034963 is 36943044612.

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 21644034963 - 2¹⁷ = 21643903891 is a prime.

It is a super-2 number, since 2×21644034963² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21644034943) 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, 3607339158 + ... + 3607339163.

It is an arithmetic number, because the mean of its divisors is an integer number (7214678322).

Almost surely, 2^21644034963 is an apocalyptic number.

21644034963 is a deficient number, since it is larger than the sum of its proper divisors (7214678325).

21644034963 is an equidigital number, since it uses as much as digits as its factorization.

21644034963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7214678324.

The product of its (nonzero) digits is 373248, while the sum is 42.

The spelling of 21644034963 in words is "twenty-one billion, six hundred forty-four million, thirty-four thousand, nine hundred sixty-three".