21643356719 has 16 divisors (see below), whose sum is σ = 22359823200. Its totient is φ = 20934120960.

The previous prime is 21643356689. The next prime is 21643356737. The reversal of 21643356719 is 91765334612.

It is a cyclic number.

It is not a de Polignac number, because 21643356719 - 2²⁰ = 21642308143 is a prime.

It is a super-2 number, since 2×21643356719² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21643856719) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6558932 + ... + 6562230.

It is an arithmetic number, because the mean of its divisors is an integer number (1397488950).

Almost surely, 2^21643356719 is an apocalyptic number.

21643356719 is a deficient number, since it is larger than the sum of its proper divisors (716466481).

21643356719 is a wasteful number, since it uses less digits than its factorization.

21643356719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4330.

The product of its digits is 816480, while the sum is 47.

The spelling of 21643356719 in words is "twenty-one billion, six hundred forty-three million, three hundred fifty-six thousand, seven hundred nineteen".