21808916919 has 48 divisors (see below), whose sum is σ = 33501262080. Its totient is φ = 13647191040.

The previous prime is 21808916911. The next prime is 21808916929. The reversal of 21808916919 is 91961980812.

It is not a de Polignac number, because 21808916919 - 2³ = 21808916911 is a prime.

It is a super-2 number, since 2×21808916919² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21808916911) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3475717 + ... + 3481985.

It is an arithmetic number, because the mean of its divisors is an integer number (697942960).

Almost surely, 2^21808916919 is an apocalyptic number.

21808916919 is a deficient number, since it is larger than the sum of its proper divisors (11692345161).

21808916919 is a wasteful number, since it uses less digits than its factorization.

21808916919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6680 (or 6677 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 54.

The spelling of 21808916919 in words is "twenty-one billion, eight hundred eight million, nine hundred sixteen thousand, nine hundred nineteen".