21653919519 has 4 divisors (see below), whose sum is σ = 28871892696. Its totient is φ = 14435946344.

The previous prime is 21653919509. The next prime is 21653919569. The reversal of 21653919519 is 91591935612.

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 21653919519 - 2¹⁶ = 21653853983 is a prime.

It is a super-2 number, since 2×21653919519² (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 (21653919509) 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, 3608986584 + ... + 3608986589.

It is an arithmetic number, because the mean of its divisors is an integer number (7217973174).

Almost surely, 2^21653919519 is an apocalyptic number.

21653919519 is a deficient number, since it is larger than the sum of its proper divisors (7217973177).

21653919519 is an equidigital number, since it uses as much as digits as its factorization.

21653919519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7217973176.

The product of its digits is 656100, while the sum is 51.

The spelling of 21653919519 in words is "twenty-one billion, six hundred fifty-three million, nine hundred nineteen thousand, five hundred nineteen".