21420219553 has 4 divisors (see below), whose sum is σ = 21422428720. Its totient is φ = 21418010388.

The previous prime is 21420219551. The next prime is 21420219599. The reversal of 21420219553 is 35591202412.

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 21420219553 - 2¹ = 21420219551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420219551) 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, 1089975 + ... + 1109452.

It is an arithmetic number, because the mean of its divisors is an integer number (5355607180).

Almost surely, 2^21420219553 is an apocalyptic number.

It is an amenable number.

21420219553 is a deficient number, since it is larger than the sum of its proper divisors (2209167).

21420219553 is an equidigital number, since it uses as much as digits as its factorization.

21420219553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2209166.

The product of its (nonzero) digits is 21600, while the sum is 34.

The spelling of 21420219553 in words is "twenty-one billion, four hundred twenty million, two hundred nineteen thousand, five hundred fifty-three".