21788235553 has 4 divisors (see below), whose sum is σ = 24900840640. Its totient is φ = 18675630468.

The previous prime is 21788235551. The next prime is 21788235569. The reversal of 21788235553 is 35553288712.

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 21788235553 - 2¹ = 21788235551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21788235497 and 21788235506.

It is not an unprimeable number, because it can be changed into a prime (21788235551) 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, 1556302533 + ... + 1556302546.

It is an arithmetic number, because the mean of its divisors is an integer number (6225210160).

Almost surely, 2^21788235553 is an apocalyptic number.

It is an amenable number.

21788235553 is a deficient number, since it is larger than the sum of its proper divisors (3112605087).

21788235553 is an equidigital number, since it uses as much as digits as its factorization.

21788235553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3112605086.

The product of its digits is 2016000, while the sum is 49.

The spelling of 21788235553 in words is "twenty-one billion, seven hundred eighty-eight million, two hundred thirty-five thousand, five hundred fifty-three".