21618528479 has 2 divisors, whose sum is σ = 21618528480. Its totient is φ = 21618528478.

The previous prime is 21618528473. The next prime is 21618528521. The reversal of 21618528479 is 97482581612.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21618528479 is a prime.

It is a super-4 number, since 4×21618528479⁴ (a number of 42 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21618528479.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21618528473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10809264239 + 10809264240.

It is an arithmetic number, because the mean of its divisors is an integer number (10809264240).

Almost surely, 2^21618528479 is an apocalyptic number.

21618528479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21618528479 is an equidigital number, since it uses as much as digits as its factorization.

21618528479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1935360, while the sum is 53.

The spelling of 21618528479 in words is "twenty-one billion, six hundred eighteen million, five hundred twenty-eight thousand, four hundred seventy-nine".