21689348449 has 4 divisors (see below), whose sum is σ = 21690180864. Its totient is φ = 21688516036.

The previous prime is 21689348423. The next prime is 21689348489. The reversal of 21689348449 is 94484398612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21689348449 - 2⁷ = 21689348321 is a prime.

It is a super-2 number, since 2×21689348449² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21689348393 and 21689348402.

It is not an unprimeable number, because it can be changed into a prime (21689348489) 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, 375817 + ... + 429670.

It is an arithmetic number, because the mean of its divisors is an integer number (5422545216).

Almost surely, 2^21689348449 is an apocalyptic number.

It is an amenable number.

21689348449 is a deficient number, since it is larger than the sum of its proper divisors (832415).

21689348449 is an equidigital number, since it uses as much as digits as its factorization.

21689348449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832414.

The product of its digits is 11943936, while the sum is 58.

The spelling of 21689348449 in words is "twenty-one billion, six hundred eighty-nine million, three hundred forty-eight thousand, four hundred forty-nine".